4C'S LEARNING CENTER
Be confident you're getting the best diamond for your money. Here you'll find unbiased information to help take the anxiety
out of this exciting time. We don't buy or sell diamonds and we don't get commissions for recommending certain retailers.
Be confident you're getting the best diamond for your money. Here you'll find unbiased information to help take the anxiety out of this exciting time. We don't buy or sell diamonds and we don't get commissions for recommending certain retailers.
DIAMOND CERTIFICATION
Before you head off to the jewelry store, there is one more 'C' to consider, and it is just as important as the first 4C's. The fifth 'C' is Certification.
The cost of a diamond is determined by its quality
At first glance, all diamonds in a jeweler's showcase might look pretty much the same, but depending on tiny differences- ones usually imperceptible to the untrained eye- two stones of identical size and shape can be worth vastly different amounts. Their value depends on their 4C's quality ratings. Learn more about the 4C's
How certification helps you shop
Before dropping a load of cash for your perfect diamond, wouldn't you be more comfortable with a second opinion, an unbiased evaluation of the diamond's quality? Of course, and this is why most diamonds are sold with grading reports from 'independent' labs. But before you open your wallet, just who is providing that independent second opinion? Is the lab owned by the jeweler's friend? Does the lab have a reputation for 'generously' over-grading? Does the lab take responsibility for their work?.
Rating agencies
Just as rating agencies provide investors with assessments of companies, giving different ratings such as AAA, AA or B+ which affect their value, grading labs provide analyses of diamonds which affect their value. Diamond grading labs have different reputations. A dealer might pay 20%, even 40%, less for a stone with a grading report from a particular lab because that lab is known to inflate the grades. Usually, everyone in the jewelry industry knows.. but not the consumer. Read more about GCAL's Standards
Protect yourself by making sure your diamond is accompanied by a gemological certificate that assures you of accurate quality information- and protects the value and liquidity of your diamond in the future.
Why ask for a GCAL Certificate?
GCAL, is the only one... the only one that puts our money where our mouth is. GCAL's cash-back policy ensures the accuracy of cut, color and clarity grades as well as the weight of GCAL graded diamonds. But the Zero Tolerance Grading Guarantee isn't the only thing that makes GCAL unique... GCAL is also the only ISO 17025 Forensic Accredited gem lab in North America, the only one offering GEMPRINT® and the only one with Diamond Profile® light analysis technology. Read more about GCAL Advantages
GCAL issues Certificates, other labs issue Reports
A diamond certificate is a warranty; a diamond report is an opinion. Although the two terms are used interchangeably and both documents grade the 4C's, they are far from the same. If you look closely at a diamond report, you will find a disclaimer of liability for errors and inaccuracies. From a legal standpoint, this means that the lab issuing the document refuses accountability for its work. A certificate, on the other hand, is a document for which the issuer accepts legal responsibility- and will make restitution for mistakes. Read more about The GCAL Guarantee
GCAL Certificates are forensic tracking documents
A diamond certificate is a tracking document that aids in recovery of stones if lost or stolen. Like a passport or a driver's license, a diamond certificate serves as an identification document- not merely a record of information. Using photo-imaging technology, a gem lab can take a distinctive light-emission portrait of any diamond that is digitized and stored in a database- as well as reproduced on a certificate. This portrait serves as a permanent 'fingerprint' that can be used to make a match if the stone is lost and later recovered. Further, this digital 'fingerprint' can be used to prove if another -- usually inferior -- stone has been substituted for yours by an unscrupulous retailer or repairman. No wonder a growing number of insurance companies offer premium discounts for 'fingerprinted' diamonds. Read more about Gemprint
GCAL's Philosophy
We believe consumers should feel confident about their diamond purchase, that's why our mission is to provide the most accurate and consistent gemological services with uncompromising integrity and unparalleled customer care. Read more about GCAL
We believe experts should stand behind their work, that's why we issue Grading Certificates, not just grading reports. Our certificates come with a money-back guarantee so you can feel good knowing you got exactly what you paid for.
We believe in doing things the right way, not the easy way, that's why we don't cut corners. With only one location in the USA, we have complete control of maintaining high standards, training and consistency.
We believe challenging ourselves leads to better performance, that's why our methods and procedures are independently audited annually, ensuring we uphold the standards of the ISO 17025 Forensic Laboratory Accreditation. Read more about ISO17025
Each panel of a GCAL Certificate tells a story to the customer.
- Panel 1
Verifies the identification process
- Panel 2
Verifies the 4C's quality grading
- Panel 3
Illustrates the quality of cutting and proportions revealing the skill of the diamond cutter
- 1Gemprint
GEMPRINT
Gemprint
Gemprint® is a non-invasive, positive identification technology that records the unique optical 'fingerprint' of each diamond. Just like a human fingerprint, every diamond has a unique Gemprint. Capturing the unique Gemprint of your diamond in the initial processing stage, allows us to positively identify and track the diamond through our process. This optical fingerprint is captured and stored in GCAL's database for future verification and identification, and a digital image is printed on every GCAL Certificate.
How it works:
Gemprint uses a sophisticated system comprising laser technology, high resolution imaging, and automated positioning to direct a focused laser beam at the center of the diamond. The light enters the diamond and is broken into many rays as it reflects and refracts off the pavilion and crown facets. As the light reflects back out of the diamond, it creates a distinct Gemprint.
Laser Inscription
Laser Inscription quickly identifies a diamond and is included with this GCAL Guaranteed Diamond Grading Certificate. GCAL certified diamonds are laser inscribed with the unique certificate number assigned to the diamond. Photomicrographs, captured at more than 50x magnification, are taken to easily communicate what is inscribed on your diamond, and can be used as an additional piece of forensic identification of your diamond.
How it works:
GCAL uses a sophisticated IR laser technology specially designed for inscribing gemstones. When this laser is focused on a diamond's surface, it graphitizes a microscopic mark. A continuous series of these marks produces the numbers and letters you see on the girdle. The laser inscription mark is extremely shallow, only about 2-5 microns deep, less than one-tenth the width of the average human hair.
4Cs GRADING
WEIGHTS & MEASUREMENTS
Precise measurement of carat weight is important - slight differences can have a large impact on the value of a diamond. GCAL weighs diamonds on precise electronic balances according to international standards. This means that the weight is measured to the thousandth of a carat, and then is rounded to the hundredth of a carat. The electronic balances at GCAL are verified daily to ensure consistent and accurate results. The diamond is then measured by an optical scanning device that captures a series of high resolution images and creates an exact 3D model of every facet and angle, providing accurate geometrical measurements of the diamond. This proportion diagram appears on your GCAL certificate.
COLOR
Diamonds are color graded on a scale from D to Z. Each letter represents a slightly more saturated color. Your diamond is examined in a standard lighting environment and is compared to a set of Precision Master Color diamonds, which each have a precise color grade. Comparison of your diamond to the Precision Master diamonds continues until the color grade is determined. The difference between each color grade is very slight, but with experience, expert graders are able to consistently determine the accurate color grade of each diamond. GCAL utilizes a unique quality control procedure for grading the color and clarity of diamonds that assures the most accurate and consistent grading possible. At least three experienced gemologists examine and grade both the color and the clarity of every diamond. (After color grading, your diamond is checked for fluorescence, its reaction to ultraviolet light. A set of Master fluorescent diamonds is used to compare the strength of fluorescence. This intrinsic property is a permanent identifying characteristic of your diamond.)
CLARITY
Clarity is graded by examining your diamond under a microscope to assess internal and external characteristics such as crystals and feathers. A gemologist first inspects the diamond in the face-up position to find obvious inclusions. To find minute inclusions, the diamond has to be viewed through the pavilion as it is slowly rotated at least 3 full times, changing the viewing angle each time. The gemologist must assess the number, size, type, position and relief of each inclusion. After thorough inspection under the microscope, a 10x loupe is used to view the diamond in 4 different positions to determine the final clarity grade. GCAL utilizes a unique quality control procedure for grading the color and clarity of diamonds that assures the most accurate and consistent grading possible. At least three experienced gemologists examine and grade both the color and the clarity of every diamond.
RESEARCH
Before grading, every diamond is tested to confirm its origin - either natural earth mined or lab grown. If a diamond's origin cannot be verified by the initial spectroscopic analysis, then it is sent to the research department where additional more advanced tests are used to determine its authenticity. Considerable investment in state-of-the-art technologies has made GCAL one of the most well-equipped gem labs in the world. Once your diamond's origin is determined, it is ready for grading.
Photomicrograph
Photomicrographs are taken of the crown and pavilion of your diamond. These photos provide a forensic record of the exact appearance and condition of your diamond, and show internal and external characteristics visible at 10x magnification. Photographs are the most accurate way to illustrate the exact appearance and location of inclusions.
HEARTS & ARROWS
Hearts & Arrows is a term used to describe the patterns visible in perfectly faceted round brilliant cut diamonds when they are examined in specialized viewers. Through these viewers, it is possible to assess the alignment and consistency of every facet by looking at the equality of light return, or the hearts and arrows patterns.
A precisely faceted round brilliant diamond exhibits a pattern of eight arrows through the crown (top) side, and a pattern of eight hearts through the pavilion (bottom) side.
GCAL is the only laboratory that takes a real photograph of each diamond in the specialized viewer. This means that the images on your GCAL Certificate are actually of your diamond. Unlike the majority of the Hearts & Arrows photos printed on other lab reports or seen online, which are either generic sample images applied to every diamond or are computer generated - neither of which guarantees that the diamond you're paying a premium for is actually deserving of the term Hearts & Arrow.
OPTICAL BRILLIANCE
GCAL directly assesses the overall return of light to the viewer, called 'brilliance'.
The Optical Brilliance image is actually a digital photograph of the diamond taken in a special lighting environment that creates a strong contrast between the bright and dark areas. The image is then processed in a proprietary computer program that calculates the percentage of brilliance and the amount of light loss. This is a scientifically accurate and repeatable way to measure brilliance. The light gray areas of the image are facet outlines resulting from image processing to provide a realistic representation of the diamond's unique faceting.
In the Optical Brilliance Analysis image on the certificate, the white represents the light return and the blue represents areas of light loss. The light return is quantified based on measurable light return (aka - performance) and then graded as: Excellent, Very Good, Good, Fair or Poor.
Since the Optical Brilliance is measured by direct assessment, meaning that it is judged based on the way each diamond actually performs rather than a theoretical model, the brilliance image of each individual diamond will always look slightly different.
Brilliance is what gives a diamond its life, and what makes a diamond shine from across a room. Diamonds with a low percentage of brilliance look dull and dark.
OPTICAL SYMMETRY
The Optical Symmetry Analysis image is a digital photograph taken of each diamond in a special lighting environment that reveals the patterns of light return. All light returned at the same angles is represented by the same color. For example, all red areas represent light being returned within a consistent angle range. Therefore, the Optical Symmetry assesses the consistency of angles and alignment of facets by looking at the equality of light return.
Since the Optical Symmetry is measured by direct assessment, meaning that it is judged based on the way each diamond actually performs rather than a theoretical model, the symmetry images of each individual diamond will always look slightly different. Like the beauty and ever changing color patterns in a kaleidoscope, each diamond reveals its unique reflective pattern of symmetry. You can judge the cut of a diamond yourself simply by examining the symmetry image-the more even the pattern, the better the symmetry
PROPORTION DIAGRAM
Each diamond is measured by an optical scanning device that captures a series of high resolution images and creates an exact 3D model of every facet and angle, providing accurate geometrical measurements of the diamond. This proportion diagram appears on your GCAL certificate.
- 2Laser Inscription
Laser Inscription
Gemprint
Gemprint® is a non-invasive, positive identification technology that records the unique optical 'fingerprint' of each diamond. Just like a human fingerprint, every diamond has a unique Gemprint. Capturing the unique Gemprint of your diamond in the initial processing stage, allows us to positively identify and track the diamond through our process. This optical fingerprint is captured and stored in GCAL's database for future verification and identification, and a digital image is printed on every GCAL Certificate.
How it works:
Gemprint uses a sophisticated system comprising laser technology, high resolution imaging, and automated positioning to direct a focused laser beam at the center of the diamond. The light enters the diamond and is broken into many rays as it reflects and refracts off the pavilion and crown facets. As the light reflects back out of the diamond, it creates a distinct Gemprint.
Laser Inscription
Laser Inscription quickly identifies a diamond and is included with this GCAL Guaranteed Diamond Grading Certificate. GCAL certified diamonds are laser inscribed with the unique certificate number assigned to the diamond. Photomicrographs, captured at more than 50x magnification, are taken to easily communicate what is inscribed on your diamond, and can be used as an additional piece of forensic identification of your diamond.
How it works:
GCAL uses a sophisticated IR laser technology specially designed for inscribing gemstones. When this laser is focused on a diamond's surface, it graphitizes a microscopic mark. A continuous series of these marks produces the numbers and letters you see on the girdle. The laser inscription mark is extremely shallow, only about 2-5 microns deep, less than one-tenth the width of the average human hair.
4Cs GRADING
WEIGHTS & MEASUREMENTS
Precise measurement of carat weight is important - slight differences can have a large impact on the value of a diamond. GCAL weighs diamonds on precise electronic balances according to international standards. This means that the weight is measured to the thousandth of a carat, and then is rounded to the hundredth of a carat. The electronic balances at GCAL are verified daily to ensure consistent and accurate results. The diamond is then measured by an optical scanning device that captures a series of high resolution images and creates an exact 3D model of every facet and angle, providing accurate geometrical measurements of the diamond. This proportion diagram appears on your GCAL certificate.
COLOR
Diamonds are color graded on a scale from D to Z. Each letter represents a slightly more saturated color. Your diamond is examined in a standard lighting environment and is compared to a set of Precision Master Color diamonds, which each have a precise color grade. Comparison of your diamond to the Precision Master diamonds continues until the color grade is determined. The difference between each color grade is very slight, but with experience, expert graders are able to consistently determine the accurate color grade of each diamond. GCAL utilizes a unique quality control procedure for grading the color and clarity of diamonds that assures the most accurate and consistent grading possible. At least three experienced gemologists examine and grade both the color and the clarity of every diamond. (After color grading, your diamond is checked for fluorescence, its reaction to ultraviolet light. A set of Master fluorescent diamonds is used to compare the strength of fluorescence. This intrinsic property is a permanent identifying characteristic of your diamond.)
CLARITY
Clarity is graded by examining your diamond under a microscope to assess internal and external characteristics such as crystals and feathers. A gemologist first inspects the diamond in the face-up position to find obvious inclusions. To find minute inclusions, the diamond has to be viewed through the pavilion as it is slowly rotated at least 3 full times, changing the viewing angle each time. The gemologist must assess the number, size, type, position and relief of each inclusion. After thorough inspection under the microscope, a 10x loupe is used to view the diamond in 4 different positions to determine the final clarity grade. GCAL utilizes a unique quality control procedure for grading the color and clarity of diamonds that assures the most accurate and consistent grading possible. At least three experienced gemologists examine and grade both the color and the clarity of every diamond.
RESEARCH
Before grading, every diamond is tested to confirm its origin - either natural earth mined or lab grown. If a diamond's origin cannot be verified by the initial spectroscopic analysis, then it is sent to the research department where additional more advanced tests are used to determine its authenticity. Considerable investment in state-of-the-art technologies has made GCAL one of the most well-equipped gem labs in the world. Once your diamond's origin is determined, it is ready for grading.
Photomicrograph
Photomicrographs are taken of the crown and pavilion of your diamond. These photos provide a forensic record of the exact appearance and condition of your diamond, and show internal and external characteristics visible at 10x magnification. Photographs are the most accurate way to illustrate the exact appearance and location of inclusions.
HEARTS & ARROWS
Hearts & Arrows is a term used to describe the patterns visible in perfectly faceted round brilliant cut diamonds when they are examined in specialized viewers. Through these viewers, it is possible to assess the alignment and consistency of every facet by looking at the equality of light return, or the hearts and arrows patterns.
A precisely faceted round brilliant diamond exhibits a pattern of eight arrows through the crown (top) side, and a pattern of eight hearts through the pavilion (bottom) side.
GCAL is the only laboratory that takes a real photograph of each diamond in the specialized viewer. This means that the images on your GCAL Certificate are actually of your diamond. Unlike the majority of the Hearts & Arrows photos printed on other lab reports or seen online, which are either generic sample images applied to every diamond or are computer generated - neither of which guarantees that the diamond you're paying a premium for is actually deserving of the term Hearts & Arrow.
OPTICAL BRILLIANCE
GCAL directly assesses the overall return of light to the viewer, called 'brilliance'.
The Optical Brilliance image is actually a digital photograph of the diamond taken in a special lighting environment that creates a strong contrast between the bright and dark areas. The image is then processed in a proprietary computer program that calculates the percentage of brilliance and the amount of light loss. This is a scientifically accurate and repeatable way to measure brilliance. The light gray areas of the image are facet outlines resulting from image processing to provide a realistic representation of the diamond's unique faceting.
In the Optical Brilliance Analysis image on the certificate, the white represents the light return and the blue represents areas of light loss. The light return is quantified based on measurable light return (aka - performance) and then graded as: Excellent, Very Good, Good, Fair or Poor.
Since the Optical Brilliance is measured by direct assessment, meaning that it is judged based on the way each diamond actually performs rather than a theoretical model, the brilliance image of each individual diamond will always look slightly different.
Brilliance is what gives a diamond its life, and what makes a diamond shine from across a room. Diamonds with a low percentage of brilliance look dull and dark.
OPTICAL SYMMETRY
The Optical Symmetry Analysis image is a digital photograph taken of each diamond in a special lighting environment that reveals the patterns of light return. All light returned at the same angles is represented by the same color. For example, all red areas represent light being returned within a consistent angle range. Therefore, the Optical Symmetry assesses the consistency of angles and alignment of facets by looking at the equality of light return.
Since the Optical Symmetry is measured by direct assessment, meaning that it is judged based on the way each diamond actually performs rather than a theoretical model, the symmetry images of each individual diamond will always look slightly different. Like the beauty and ever changing color patterns in a kaleidoscope, each diamond reveals its unique reflective pattern of symmetry. You can judge the cut of a diamond yourself simply by examining the symmetry image-the more even the pattern, the better the symmetry
PROPORTION DIAGRAM
Each diamond is measured by an optical scanning device that captures a series of high resolution images and creates an exact 3D model of every facet and angle, providing accurate geometrical measurements of the diamond. This proportion diagram appears on your GCAL certificate.
- 34C's Grading
4C's Grading
Gemprint
Gemprint® is a non-invasive, positive identification technology that records the unique optical 'fingerprint' of each diamond. Just like a human fingerprint, every diamond has a unique Gemprint. Capturing the unique Gemprint of your diamond in the initial processing stage, allows us to positively identify and track the diamond through our process. This optical fingerprint is captured and stored in GCAL's database for future verification and identification, and a digital image is printed on every GCAL Certificate.
How it works:
Gemprint uses a sophisticated system comprising laser technology, high resolution imaging, and automated positioning to direct a focused laser beam at the center of the diamond. The light enters the diamond and is broken into many rays as it reflects and refracts off the pavilion and crown facets. As the light reflects back out of the diamond, it creates a distinct Gemprint.
Laser Inscription
Laser Inscription quickly identifies a diamond and is included with this GCAL Guaranteed Diamond Grading Certificate. GCAL certified diamonds are laser inscribed with the unique certificate number assigned to the diamond. Photomicrographs, captured at more than 50x magnification, are taken to easily communicate what is inscribed on your diamond, and can be used as an additional piece of forensic identification of your diamond.
How it works:
GCAL uses a sophisticated IR laser technology specially designed for inscribing gemstones. When this laser is focused on a diamond's surface, it graphitizes a microscopic mark. A continuous series of these marks produces the numbers and letters you see on the girdle. The laser inscription mark is extremely shallow, only about 2-5 microns deep, less than one-tenth the width of the average human hair.
4Cs GRADING
WEIGHTS & MEASUREMENTS
Precise measurement of carat weight is important - slight differences can have a large impact on the value of a diamond. GCAL weighs diamonds on precise electronic balances according to international standards. This means that the weight is measured to the thousandth of a carat, and then is rounded to the hundredth of a carat. The electronic balances at GCAL are verified daily to ensure consistent and accurate results. The diamond is then measured by an optical scanning device that captures a series of high resolution images and creates an exact 3D model of every facet and angle, providing accurate geometrical measurements of the diamond. This proportion diagram appears on your GCAL certificate.
COLOR
Diamonds are color graded on a scale from D to Z. Each letter represents a slightly more saturated color. Your diamond is examined in a standard lighting environment and is compared to a set of Precision Master Color diamonds, which each have a precise color grade. Comparison of your diamond to the Precision Master diamonds continues until the color grade is determined. The difference between each color grade is very slight, but with experience, expert graders are able to consistently determine the accurate color grade of each diamond. GCAL utilizes a unique quality control procedure for grading the color and clarity of diamonds that assures the most accurate and consistent grading possible. At least three experienced gemologists examine and grade both the color and the clarity of every diamond. (After color grading, your diamond is checked for fluorescence, its reaction to ultraviolet light. A set of Master fluorescent diamonds is used to compare the strength of fluorescence. This intrinsic property is a permanent identifying characteristic of your diamond.)
CLARITY
Clarity is graded by examining your diamond under a microscope to assess internal and external characteristics such as crystals and feathers. A gemologist first inspects the diamond in the face-up position to find obvious inclusions. To find minute inclusions, the diamond has to be viewed through the pavilion as it is slowly rotated at least 3 full times, changing the viewing angle each time. The gemologist must assess the number, size, type, position and relief of each inclusion. After thorough inspection under the microscope, a 10x loupe is used to view the diamond in 4 different positions to determine the final clarity grade. GCAL utilizes a unique quality control procedure for grading the color and clarity of diamonds that assures the most accurate and consistent grading possible. At least three experienced gemologists examine and grade both the color and the clarity of every diamond.
RESEARCH
Before grading, every diamond is tested to confirm its origin - either natural earth mined or lab grown. If a diamond's origin cannot be verified by the initial spectroscopic analysis, then it is sent to the research department where additional more advanced tests are used to determine its authenticity. Considerable investment in state-of-the-art technologies has made GCAL one of the most well-equipped gem labs in the world. Once your diamond's origin is determined, it is ready for grading.
Photomicrograph
Photomicrographs are taken of the crown and pavilion of your diamond. These photos provide a forensic record of the exact appearance and condition of your diamond, and show internal and external characteristics visible at 10x magnification. Photographs are the most accurate way to illustrate the exact appearance and location of inclusions.
HEARTS & ARROWS
Hearts & Arrows is a term used to describe the patterns visible in perfectly faceted round brilliant cut diamonds when they are examined in specialized viewers. Through these viewers, it is possible to assess the alignment and consistency of every facet by looking at the equality of light return, or the hearts and arrows patterns.
A precisely faceted round brilliant diamond exhibits a pattern of eight arrows through the crown (top) side, and a pattern of eight hearts through the pavilion (bottom) side.
GCAL is the only laboratory that takes a real photograph of each diamond in the specialized viewer. This means that the images on your GCAL Certificate are actually of your diamond. Unlike the majority of the Hearts & Arrows photos printed on other lab reports or seen online, which are either generic sample images applied to every diamond or are computer generated - neither of which guarantees that the diamond you're paying a premium for is actually deserving of the term Hearts & Arrow.
OPTICAL BRILLIANCE
GCAL directly assesses the overall return of light to the viewer, called 'brilliance'.
The Optical Brilliance image is actually a digital photograph of the diamond taken in a special lighting environment that creates a strong contrast between the bright and dark areas. The image is then processed in a proprietary computer program that calculates the percentage of brilliance and the amount of light loss. This is a scientifically accurate and repeatable way to measure brilliance. The light gray areas of the image are facet outlines resulting from image processing to provide a realistic representation of the diamond's unique faceting.
In the Optical Brilliance Analysis image on the certificate, the white represents the light return and the blue represents areas of light loss. The light return is quantified based on measurable light return (aka - performance) and then graded as: Excellent, Very Good, Good, Fair or Poor.
Since the Optical Brilliance is measured by direct assessment, meaning that it is judged based on the way each diamond actually performs rather than a theoretical model, the brilliance image of each individual diamond will always look slightly different.
Brilliance is what gives a diamond its life, and what makes a diamond shine from across a room. Diamonds with a low percentage of brilliance look dull and dark.
OPTICAL SYMMETRY
The Optical Symmetry Analysis image is a digital photograph taken of each diamond in a special lighting environment that reveals the patterns of light return. All light returned at the same angles is represented by the same color. For example, all red areas represent light being returned within a consistent angle range. Therefore, the Optical Symmetry assesses the consistency of angles and alignment of facets by looking at the equality of light return.
Since the Optical Symmetry is measured by direct assessment, meaning that it is judged based on the way each diamond actually performs rather than a theoretical model, the symmetry images of each individual diamond will always look slightly different. Like the beauty and ever changing color patterns in a kaleidoscope, each diamond reveals its unique reflective pattern of symmetry. You can judge the cut of a diamond yourself simply by examining the symmetry image-the more even the pattern, the better the symmetry
PROPORTION DIAGRAM
Each diamond is measured by an optical scanning device that captures a series of high resolution images and creates an exact 3D model of every facet and angle, providing accurate geometrical measurements of the diamond. This proportion diagram appears on your GCAL certificate.
- 4Photomicrograph
Photomicrograph
Gemprint
Gemprint® is a non-invasive, positive identification technology that records the unique optical 'fingerprint' of each diamond. Just like a human fingerprint, every diamond has a unique Gemprint. Capturing the unique Gemprint of your diamond in the initial processing stage, allows us to positively identify and track the diamond through our process. This optical fingerprint is captured and stored in GCAL's database for future verification and identification, and a digital image is printed on every GCAL Certificate.
How it works:
Gemprint uses a sophisticated system comprising laser technology, high resolution imaging, and automated positioning to direct a focused laser beam at the center of the diamond. The light enters the diamond and is broken into many rays as it reflects and refracts off the pavilion and crown facets. As the light reflects back out of the diamond, it creates a distinct Gemprint.
Laser Inscription
Laser Inscription quickly identifies a diamond and is included with this GCAL Guaranteed Diamond Grading Certificate. GCAL certified diamonds are laser inscribed with the unique certificate number assigned to the diamond. Photomicrographs, captured at more than 50x magnification, are taken to easily communicate what is inscribed on your diamond, and can be used as an additional piece of forensic identification of your diamond.
How it works:
GCAL uses a sophisticated IR laser technology specially designed for inscribing gemstones. When this laser is focused on a diamond's surface, it graphitizes a microscopic mark. A continuous series of these marks produces the numbers and letters you see on the girdle. The laser inscription mark is extremely shallow, only about 2-5 microns deep, less than one-tenth the width of the average human hair.
4Cs GRADING
WEIGHTS & MEASUREMENTS
Precise measurement of carat weight is important - slight differences can have a large impact on the value of a diamond. GCAL weighs diamonds on precise electronic balances according to international standards. This means that the weight is measured to the thousandth of a carat, and then is rounded to the hundredth of a carat. The electronic balances at GCAL are verified daily to ensure consistent and accurate results. The diamond is then measured by an optical scanning device that captures a series of high resolution images and creates an exact 3D model of every facet and angle, providing accurate geometrical measurements of the diamond. This proportion diagram appears on your GCAL certificate.
COLOR
Diamonds are color graded on a scale from D to Z. Each letter represents a slightly more saturated color. Your diamond is examined in a standard lighting environment and is compared to a set of Precision Master Color diamonds, which each have a precise color grade. Comparison of your diamond to the Precision Master diamonds continues until the color grade is determined. The difference between each color grade is very slight, but with experience, expert graders are able to consistently determine the accurate color grade of each diamond. GCAL utilizes a unique quality control procedure for grading the color and clarity of diamonds that assures the most accurate and consistent grading possible. At least three experienced gemologists examine and grade both the color and the clarity of every diamond. (After color grading, your diamond is checked for fluorescence, its reaction to ultraviolet light. A set of Master fluorescent diamonds is used to compare the strength of fluorescence. This intrinsic property is a permanent identifying characteristic of your diamond.)
CLARITY
Clarity is graded by examining your diamond under a microscope to assess internal and external characteristics such as crystals and feathers. A gemologist first inspects the diamond in the face-up position to find obvious inclusions. To find minute inclusions, the diamond has to be viewed through the pavilion as it is slowly rotated at least 3 full times, changing the viewing angle each time. The gemologist must assess the number, size, type, position and relief of each inclusion. After thorough inspection under the microscope, a 10x loupe is used to view the diamond in 4 different positions to determine the final clarity grade. GCAL utilizes a unique quality control procedure for grading the color and clarity of diamonds that assures the most accurate and consistent grading possible. At least three experienced gemologists examine and grade both the color and the clarity of every diamond.
RESEARCH
Before grading, every diamond is tested to confirm its origin - either natural earth mined or lab grown. If a diamond's origin cannot be verified by the initial spectroscopic analysis, then it is sent to the research department where additional more advanced tests are used to determine its authenticity. Considerable investment in state-of-the-art technologies has made GCAL one of the most well-equipped gem labs in the world. Once your diamond's origin is determined, it is ready for grading.
Photomicrograph
Photomicrographs are taken of the crown and pavilion of your diamond. These photos provide a forensic record of the exact appearance and condition of your diamond, and show internal and external characteristics visible at 10x magnification. Photographs are the most accurate way to illustrate the exact appearance and location of inclusions.
HEARTS & ARROWS
Hearts & Arrows is a term used to describe the patterns visible in perfectly faceted round brilliant cut diamonds when they are examined in specialized viewers. Through these viewers, it is possible to assess the alignment and consistency of every facet by looking at the equality of light return, or the hearts and arrows patterns.
A precisely faceted round brilliant diamond exhibits a pattern of eight arrows through the crown (top) side, and a pattern of eight hearts through the pavilion (bottom) side.
GCAL is the only laboratory that takes a real photograph of each diamond in the specialized viewer. This means that the images on your GCAL Certificate are actually of your diamond. Unlike the majority of the Hearts & Arrows photos printed on other lab reports or seen online, which are either generic sample images applied to every diamond or are computer generated - neither of which guarantees that the diamond you're paying a premium for is actually deserving of the term Hearts & Arrow.
OPTICAL BRILLIANCE
GCAL directly assesses the overall return of light to the viewer, called 'brilliance'.
The Optical Brilliance image is actually a digital photograph of the diamond taken in a special lighting environment that creates a strong contrast between the bright and dark areas. The image is then processed in a proprietary computer program that calculates the percentage of brilliance and the amount of light loss. This is a scientifically accurate and repeatable way to measure brilliance. The light gray areas of the image are facet outlines resulting from image processing to provide a realistic representation of the diamond's unique faceting.
In the Optical Brilliance Analysis image on the certificate, the white represents the light return and the blue represents areas of light loss. The light return is quantified based on measurable light return (aka - performance) and then graded as: Excellent, Very Good, Good, Fair or Poor.
Since the Optical Brilliance is measured by direct assessment, meaning that it is judged based on the way each diamond actually performs rather than a theoretical model, the brilliance image of each individual diamond will always look slightly different.
Brilliance is what gives a diamond its life, and what makes a diamond shine from across a room. Diamonds with a low percentage of brilliance look dull and dark.
OPTICAL SYMMETRY
The Optical Symmetry Analysis image is a digital photograph taken of each diamond in a special lighting environment that reveals the patterns of light return. All light returned at the same angles is represented by the same color. For example, all red areas represent light being returned within a consistent angle range. Therefore, the Optical Symmetry assesses the consistency of angles and alignment of facets by looking at the equality of light return.
Since the Optical Symmetry is measured by direct assessment, meaning that it is judged based on the way each diamond actually performs rather than a theoretical model, the symmetry images of each individual diamond will always look slightly different. Like the beauty and ever changing color patterns in a kaleidoscope, each diamond reveals its unique reflective pattern of symmetry. You can judge the cut of a diamond yourself simply by examining the symmetry image-the more even the pattern, the better the symmetry
PROPORTION DIAGRAM
Each diamond is measured by an optical scanning device that captures a series of high resolution images and creates an exact 3D model of every facet and angle, providing accurate geometrical measurements of the diamond. This proportion diagram appears on your GCAL certificate.
- 5Hearts & Arrow
Hearts & Arrow
Gemprint
Gemprint® is a non-invasive, positive identification technology that records the unique optical 'fingerprint' of each diamond. Just like a human fingerprint, every diamond has a unique Gemprint. Capturing the unique Gemprint of your diamond in the initial processing stage, allows us to positively identify and track the diamond through our process. This optical fingerprint is captured and stored in GCAL's database for future verification and identification, and a digital image is printed on every GCAL Certificate.
How it works:
Gemprint uses a sophisticated system comprising laser technology, high resolution imaging, and automated positioning to direct a focused laser beam at the center of the diamond. The light enters the diamond and is broken into many rays as it reflects and refracts off the pavilion and crown facets. As the light reflects back out of the diamond, it creates a distinct Gemprint.
Laser Inscription
Laser Inscription quickly identifies a diamond and is included with this GCAL Guaranteed Diamond Grading Certificate. GCAL certified diamonds are laser inscribed with the unique certificate number assigned to the diamond. Photomicrographs, captured at more than 50x magnification, are taken to easily communicate what is inscribed on your diamond, and can be used as an additional piece of forensic identification of your diamond.
How it works:
GCAL uses a sophisticated IR laser technology specially designed for inscribing gemstones. When this laser is focused on a diamond's surface, it graphitizes a microscopic mark. A continuous series of these marks produces the numbers and letters you see on the girdle. The laser inscription mark is extremely shallow, only about 2-5 microns deep, less than one-tenth the width of the average human hair.
4Cs GRADING
WEIGHTS & MEASUREMENTS
Precise measurement of carat weight is important - slight differences can have a large impact on the value of a diamond. GCAL weighs diamonds on precise electronic balances according to international standards. This means that the weight is measured to the thousandth of a carat, and then is rounded to the hundredth of a carat. The electronic balances at GCAL are verified daily to ensure consistent and accurate results. The diamond is then measured by an optical scanning device that captures a series of high resolution images and creates an exact 3D model of every facet and angle, providing accurate geometrical measurements of the diamond. This proportion diagram appears on your GCAL certificate.
COLOR
Diamonds are color graded on a scale from D to Z. Each letter represents a slightly more saturated color. Your diamond is examined in a standard lighting environment and is compared to a set of Precision Master Color diamonds, which each have a precise color grade. Comparison of your diamond to the Precision Master diamonds continues until the color grade is determined. The difference between each color grade is very slight, but with experience, expert graders are able to consistently determine the accurate color grade of each diamond. GCAL utilizes a unique quality control procedure for grading the color and clarity of diamonds that assures the most accurate and consistent grading possible. At least three experienced gemologists examine and grade both the color and the clarity of every diamond. (After color grading, your diamond is checked for fluorescence, its reaction to ultraviolet light. A set of Master fluorescent diamonds is used to compare the strength of fluorescence. This intrinsic property is a permanent identifying characteristic of your diamond.)
CLARITY
Clarity is graded by examining your diamond under a microscope to assess internal and external characteristics such as crystals and feathers. A gemologist first inspects the diamond in the face-up position to find obvious inclusions. To find minute inclusions, the diamond has to be viewed through the pavilion as it is slowly rotated at least 3 full times, changing the viewing angle each time. The gemologist must assess the number, size, type, position and relief of each inclusion. After thorough inspection under the microscope, a 10x loupe is used to view the diamond in 4 different positions to determine the final clarity grade. GCAL utilizes a unique quality control procedure for grading the color and clarity of diamonds that assures the most accurate and consistent grading possible. At least three experienced gemologists examine and grade both the color and the clarity of every diamond.
RESEARCH
Before grading, every diamond is tested to confirm its origin - either natural earth mined or lab grown. If a diamond's origin cannot be verified by the initial spectroscopic analysis, then it is sent to the research department where additional more advanced tests are used to determine its authenticity. Considerable investment in state-of-the-art technologies has made GCAL one of the most well-equipped gem labs in the world. Once your diamond's origin is determined, it is ready for grading.
Photomicrograph
Photomicrographs are taken of the crown and pavilion of your diamond. These photos provide a forensic record of the exact appearance and condition of your diamond, and show internal and external characteristics visible at 10x magnification. Photographs are the most accurate way to illustrate the exact appearance and location of inclusions.
HEARTS & ARROWS
Hearts & Arrows is a term used to describe the patterns visible in perfectly faceted round brilliant cut diamonds when they are examined in specialized viewers. Through these viewers, it is possible to assess the alignment and consistency of every facet by looking at the equality of light return, or the hearts and arrows patterns.
A precisely faceted round brilliant diamond exhibits a pattern of eight arrows through the crown (top) side, and a pattern of eight hearts through the pavilion (bottom) side.
GCAL is the only laboratory that takes a real photograph of each diamond in the specialized viewer. This means that the images on your GCAL Certificate are actually of your diamond. Unlike the majority of the Hearts & Arrows photos printed on other lab reports or seen online, which are either generic sample images applied to every diamond or are computer generated - neither of which guarantees that the diamond you're paying a premium for is actually deserving of the term Hearts & Arrow.
OPTICAL BRILLIANCE
GCAL directly assesses the overall return of light to the viewer, called 'brilliance'.
The Optical Brilliance image is actually a digital photograph of the diamond taken in a special lighting environment that creates a strong contrast between the bright and dark areas. The image is then processed in a proprietary computer program that calculates the percentage of brilliance and the amount of light loss. This is a scientifically accurate and repeatable way to measure brilliance. The light gray areas of the image are facet outlines resulting from image processing to provide a realistic representation of the diamond's unique faceting.
In the Optical Brilliance Analysis image on the certificate, the white represents the light return and the blue represents areas of light loss. The light return is quantified based on measurable light return (aka - performance) and then graded as: Excellent, Very Good, Good, Fair or Poor.
Since the Optical Brilliance is measured by direct assessment, meaning that it is judged based on the way each diamond actually performs rather than a theoretical model, the brilliance image of each individual diamond will always look slightly different.
Brilliance is what gives a diamond its life, and what makes a diamond shine from across a room. Diamonds with a low percentage of brilliance look dull and dark.
OPTICAL SYMMETRY
The Optical Symmetry Analysis image is a digital photograph taken of each diamond in a special lighting environment that reveals the patterns of light return. All light returned at the same angles is represented by the same color. For example, all red areas represent light being returned within a consistent angle range. Therefore, the Optical Symmetry assesses the consistency of angles and alignment of facets by looking at the equality of light return.
Since the Optical Symmetry is measured by direct assessment, meaning that it is judged based on the way each diamond actually performs rather than a theoretical model, the symmetry images of each individual diamond will always look slightly different. Like the beauty and ever changing color patterns in a kaleidoscope, each diamond reveals its unique reflective pattern of symmetry. You can judge the cut of a diamond yourself simply by examining the symmetry image-the more even the pattern, the better the symmetry
PROPORTION DIAGRAM
Each diamond is measured by an optical scanning device that captures a series of high resolution images and creates an exact 3D model of every facet and angle, providing accurate geometrical measurements of the diamond. This proportion diagram appears on your GCAL certificate.
- 6Optical Brilliance
Optical Brilliance
Gemprint
Gemprint® is a non-invasive, positive identification technology that records the unique optical 'fingerprint' of each diamond. Just like a human fingerprint, every diamond has a unique Gemprint. Capturing the unique Gemprint of your diamond in the initial processing stage, allows us to positively identify and track the diamond through our process. This optical fingerprint is captured and stored in GCAL's database for future verification and identification, and a digital image is printed on every GCAL Certificate.
How it works:
Gemprint uses a sophisticated system comprising laser technology, high resolution imaging, and automated positioning to direct a focused laser beam at the center of the diamond. The light enters the diamond and is broken into many rays as it reflects and refracts off the pavilion and crown facets. As the light reflects back out of the diamond, it creates a distinct Gemprint.
Laser Inscription
Laser Inscription quickly identifies a diamond and is included with this GCAL Guaranteed Diamond Grading Certificate. GCAL certified diamonds are laser inscribed with the unique certificate number assigned to the diamond. Photomicrographs, captured at more than 50x magnification, are taken to easily communicate what is inscribed on your diamond, and can be used as an additional piece of forensic identification of your diamond.
How it works:
GCAL uses a sophisticated IR laser technology specially designed for inscribing gemstones. When this laser is focused on a diamond's surface, it graphitizes a microscopic mark. A continuous series of these marks produces the numbers and letters you see on the girdle. The laser inscription mark is extremely shallow, only about 2-5 microns deep, less than one-tenth the width of the average human hair.
4Cs GRADING
WEIGHTS & MEASUREMENTS
Precise measurement of carat weight is important - slight differences can have a large impact on the value of a diamond. GCAL weighs diamonds on precise electronic balances according to international standards. This means that the weight is measured to the thousandth of a carat, and then is rounded to the hundredth of a carat. The electronic balances at GCAL are verified daily to ensure consistent and accurate results. The diamond is then measured by an optical scanning device that captures a series of high resolution images and creates an exact 3D model of every facet and angle, providing accurate geometrical measurements of the diamond. This proportion diagram appears on your GCAL certificate.
COLOR
Diamonds are color graded on a scale from D to Z. Each letter represents a slightly more saturated color. Your diamond is examined in a standard lighting environment and is compared to a set of Precision Master Color diamonds, which each have a precise color grade. Comparison of your diamond to the Precision Master diamonds continues until the color grade is determined. The difference between each color grade is very slight, but with experience, expert graders are able to consistently determine the accurate color grade of each diamond. GCAL utilizes a unique quality control procedure for grading the color and clarity of diamonds that assures the most accurate and consistent grading possible. At least three experienced gemologists examine and grade both the color and the clarity of every diamond. (After color grading, your diamond is checked for fluorescence, its reaction to ultraviolet light. A set of Master fluorescent diamonds is used to compare the strength of fluorescence. This intrinsic property is a permanent identifying characteristic of your diamond.)
CLARITY
Clarity is graded by examining your diamond under a microscope to assess internal and external characteristics such as crystals and feathers. A gemologist first inspects the diamond in the face-up position to find obvious inclusions. To find minute inclusions, the diamond has to be viewed through the pavilion as it is slowly rotated at least 3 full times, changing the viewing angle each time. The gemologist must assess the number, size, type, position and relief of each inclusion. After thorough inspection under the microscope, a 10x loupe is used to view the diamond in 4 different positions to determine the final clarity grade. GCAL utilizes a unique quality control procedure for grading the color and clarity of diamonds that assures the most accurate and consistent grading possible. At least three experienced gemologists examine and grade both the color and the clarity of every diamond.
RESEARCH
Before grading, every diamond is tested to confirm its origin - either natural earth mined or lab grown. If a diamond's origin cannot be verified by the initial spectroscopic analysis, then it is sent to the research department where additional more advanced tests are used to determine its authenticity. Considerable investment in state-of-the-art technologies has made GCAL one of the most well-equipped gem labs in the world. Once your diamond's origin is determined, it is ready for grading.
Photomicrograph
Photomicrographs are taken of the crown and pavilion of your diamond. These photos provide a forensic record of the exact appearance and condition of your diamond, and show internal and external characteristics visible at 10x magnification. Photographs are the most accurate way to illustrate the exact appearance and location of inclusions.
HEARTS & ARROWS
Hearts & Arrows is a term used to describe the patterns visible in perfectly faceted round brilliant cut diamonds when they are examined in specialized viewers. Through these viewers, it is possible to assess the alignment and consistency of every facet by looking at the equality of light return, or the hearts and arrows patterns.
A precisely faceted round brilliant diamond exhibits a pattern of eight arrows through the crown (top) side, and a pattern of eight hearts through the pavilion (bottom) side.
GCAL is the only laboratory that takes a real photograph of each diamond in the specialized viewer. This means that the images on your GCAL Certificate are actually of your diamond. Unlike the majority of the Hearts & Arrows photos printed on other lab reports or seen online, which are either generic sample images applied to every diamond or are computer generated - neither of which guarantees that the diamond you're paying a premium for is actually deserving of the term Hearts & Arrow.
OPTICAL BRILLIANCE
GCAL directly assesses the overall return of light to the viewer, called 'brilliance'.
The Optical Brilliance image is actually a digital photograph of the diamond taken in a special lighting environment that creates a strong contrast between the bright and dark areas. The image is then processed in a proprietary computer program that calculates the percentage of brilliance and the amount of light loss. This is a scientifically accurate and repeatable way to measure brilliance. The light gray areas of the image are facet outlines resulting from image processing to provide a realistic representation of the diamond's unique faceting.
In the Optical Brilliance Analysis image on the certificate, the white represents the light return and the blue represents areas of light loss. The light return is quantified based on measurable light return (aka - performance) and then graded as: Excellent, Very Good, Good, Fair or Poor.
Since the Optical Brilliance is measured by direct assessment, meaning that it is judged based on the way each diamond actually performs rather than a theoretical model, the brilliance image of each individual diamond will always look slightly different.
Brilliance is what gives a diamond its life, and what makes a diamond shine from across a room. Diamonds with a low percentage of brilliance look dull and dark.
OPTICAL SYMMETRY
The Optical Symmetry Analysis image is a digital photograph taken of each diamond in a special lighting environment that reveals the patterns of light return. All light returned at the same angles is represented by the same color. For example, all red areas represent light being returned within a consistent angle range. Therefore, the Optical Symmetry assesses the consistency of angles and alignment of facets by looking at the equality of light return.
Since the Optical Symmetry is measured by direct assessment, meaning that it is judged based on the way each diamond actually performs rather than a theoretical model, the symmetry images of each individual diamond will always look slightly different. Like the beauty and ever changing color patterns in a kaleidoscope, each diamond reveals its unique reflective pattern of symmetry. You can judge the cut of a diamond yourself simply by examining the symmetry image-the more even the pattern, the better the symmetry
PROPORTION DIAGRAM
Each diamond is measured by an optical scanning device that captures a series of high resolution images and creates an exact 3D model of every facet and angle, providing accurate geometrical measurements of the diamond. This proportion diagram appears on your GCAL certificate.
- 7Optical Symmetry
Optical Symmetry
Gemprint
Gemprint® is a non-invasive, positive identification technology that records the unique optical 'fingerprint' of each diamond. Just like a human fingerprint, every diamond has a unique Gemprint. Capturing the unique Gemprint of your diamond in the initial processing stage, allows us to positively identify and track the diamond through our process. This optical fingerprint is captured and stored in GCAL's database for future verification and identification, and a digital image is printed on every GCAL Certificate.
How it works:
Gemprint uses a sophisticated system comprising laser technology, high resolution imaging, and automated positioning to direct a focused laser beam at the center of the diamond. The light enters the diamond and is broken into many rays as it reflects and refracts off the pavilion and crown facets. As the light reflects back out of the diamond, it creates a distinct Gemprint.
Laser Inscription
Laser Inscription quickly identifies a diamond and is included with this GCAL Guaranteed Diamond Grading Certificate. GCAL certified diamonds are laser inscribed with the unique certificate number assigned to the diamond. Photomicrographs, captured at more than 50x magnification, are taken to easily communicate what is inscribed on your diamond, and can be used as an additional piece of forensic identification of your diamond.
How it works:
GCAL uses a sophisticated IR laser technology specially designed for inscribing gemstones. When this laser is focused on a diamond's surface, it graphitizes a microscopic mark. A continuous series of these marks produces the numbers and letters you see on the girdle. The laser inscription mark is extremely shallow, only about 2-5 microns deep, less than one-tenth the width of the average human hair.
4Cs GRADING
WEIGHTS & MEASUREMENTS
Precise measurement of carat weight is important - slight differences can have a large impact on the value of a diamond. GCAL weighs diamonds on precise electronic balances according to international standards. This means that the weight is measured to the thousandth of a carat, and then is rounded to the hundredth of a carat. The electronic balances at GCAL are verified daily to ensure consistent and accurate results. The diamond is then measured by an optical scanning device that captures a series of high resolution images and creates an exact 3D model of every facet and angle, providing accurate geometrical measurements of the diamond. This proportion diagram appears on your GCAL certificate.
COLOR
Diamonds are color graded on a scale from D to Z. Each letter represents a slightly more saturated color. Your diamond is examined in a standard lighting environment and is compared to a set of Precision Master Color diamonds, which each have a precise color grade. Comparison of your diamond to the Precision Master diamonds continues until the color grade is determined. The difference between each color grade is very slight, but with experience, expert graders are able to consistently determine the accurate color grade of each diamond. GCAL utilizes a unique quality control procedure for grading the color and clarity of diamonds that assures the most accurate and consistent grading possible. At least three experienced gemologists examine and grade both the color and the clarity of every diamond. (After color grading, your diamond is checked for fluorescence, its reaction to ultraviolet light. A set of Master fluorescent diamonds is used to compare the strength of fluorescence. This intrinsic property is a permanent identifying characteristic of your diamond.)
CLARITY
Clarity is graded by examining your diamond under a microscope to assess internal and external characteristics such as crystals and feathers. A gemologist first inspects the diamond in the face-up position to find obvious inclusions. To find minute inclusions, the diamond has to be viewed through the pavilion as it is slowly rotated at least 3 full times, changing the viewing angle each time. The gemologist must assess the number, size, type, position and relief of each inclusion. After thorough inspection under the microscope, a 10x loupe is used to view the diamond in 4 different positions to determine the final clarity grade. GCAL utilizes a unique quality control procedure for grading the color and clarity of diamonds that assures the most accurate and consistent grading possible. At least three experienced gemologists examine and grade both the color and the clarity of every diamond.
RESEARCH
Before grading, every diamond is tested to confirm its origin - either natural earth mined or lab grown. If a diamond's origin cannot be verified by the initial spectroscopic analysis, then it is sent to the research department where additional more advanced tests are used to determine its authenticity. Considerable investment in state-of-the-art technologies has made GCAL one of the most well-equipped gem labs in the world. Once your diamond's origin is determined, it is ready for grading.
Photomicrograph
Photomicrographs are taken of the crown and pavilion of your diamond. These photos provide a forensic record of the exact appearance and condition of your diamond, and show internal and external characteristics visible at 10x magnification. Photographs are the most accurate way to illustrate the exact appearance and location of inclusions.
HEARTS & ARROWS
Hearts & Arrows is a term used to describe the patterns visible in perfectly faceted round brilliant cut diamonds when they are examined in specialized viewers. Through these viewers, it is possible to assess the alignment and consistency of every facet by looking at the equality of light return, or the hearts and arrows patterns.
A precisely faceted round brilliant diamond exhibits a pattern of eight arrows through the crown (top) side, and a pattern of eight hearts through the pavilion (bottom) side.
GCAL is the only laboratory that takes a real photograph of each diamond in the specialized viewer. This means that the images on your GCAL Certificate are actually of your diamond. Unlike the majority of the Hearts & Arrows photos printed on other lab reports or seen online, which are either generic sample images applied to every diamond or are computer generated - neither of which guarantees that the diamond you're paying a premium for is actually deserving of the term Hearts & Arrow.
OPTICAL BRILLIANCE
GCAL directly assesses the overall return of light to the viewer, called 'brilliance'.
The Optical Brilliance image is actually a digital photograph of the diamond taken in a special lighting environment that creates a strong contrast between the bright and dark areas. The image is then processed in a proprietary computer program that calculates the percentage of brilliance and the amount of light loss. This is a scientifically accurate and repeatable way to measure brilliance. The light gray areas of the image are facet outlines resulting from image processing to provide a realistic representation of the diamond's unique faceting.
In the Optical Brilliance Analysis image on the certificate, the white represents the light return and the blue represents areas of light loss. The light return is quantified based on measurable light return (aka - performance) and then graded as: Excellent, Very Good, Good, Fair or Poor.
Since the Optical Brilliance is measured by direct assessment, meaning that it is judged based on the way each diamond actually performs rather than a theoretical model, the brilliance image of each individual diamond will always look slightly different.
Brilliance is what gives a diamond its life, and what makes a diamond shine from across a room. Diamonds with a low percentage of brilliance look dull and dark.
OPTICAL SYMMETRY
The Optical Symmetry Analysis image is a digital photograph taken of each diamond in a special lighting environment that reveals the patterns of light return. All light returned at the same angles is represented by the same color. For example, all red areas represent light being returned within a consistent angle range. Therefore, the Optical Symmetry assesses the consistency of angles and alignment of facets by looking at the equality of light return.
Since the Optical Symmetry is measured by direct assessment, meaning that it is judged based on the way each diamond actually performs rather than a theoretical model, the symmetry images of each individual diamond will always look slightly different. Like the beauty and ever changing color patterns in a kaleidoscope, each diamond reveals its unique reflective pattern of symmetry. You can judge the cut of a diamond yourself simply by examining the symmetry image-the more even the pattern, the better the symmetry
PROPORTION DIAGRAM
Each diamond is measured by an optical scanning device that captures a series of high resolution images and creates an exact 3D model of every facet and angle, providing accurate geometrical measurements of the diamond. This proportion diagram appears on your GCAL certificate.
- 8Proportion Diagram
Proportion Diagram
Gemprint
Gemprint® is a non-invasive, positive identification technology that records the unique optical 'fingerprint' of each diamond. Just like a human fingerprint, every diamond has a unique Gemprint. Capturing the unique Gemprint of your diamond in the initial processing stage, allows us to positively identify and track the diamond through our process. This optical fingerprint is captured and stored in GCAL's database for future verification and identification, and a digital image is printed on every GCAL Certificate.
How it works:
Gemprint uses a sophisticated system comprising laser technology, high resolution imaging, and automated positioning to direct a focused laser beam at the center of the diamond. The light enters the diamond and is broken into many rays as it reflects and refracts off the pavilion and crown facets. As the light reflects back out of the diamond, it creates a distinct Gemprint.
Laser Inscription
Laser Inscription quickly identifies a diamond and is included with this GCAL Guaranteed Diamond Grading Certificate. GCAL certified diamonds are laser inscribed with the unique certificate number assigned to the diamond. Photomicrographs, captured at more than 50x magnification, are taken to easily communicate what is inscribed on your diamond, and can be used as an additional piece of forensic identification of your diamond.
How it works:
GCAL uses a sophisticated IR laser technology specially designed for inscribing gemstones. When this laser is focused on a diamond's surface, it graphitizes a microscopic mark. A continuous series of these marks produces the numbers and letters you see on the girdle. The laser inscription mark is extremely shallow, only about 2-5 microns deep, less than one-tenth the width of the average human hair.
4Cs GRADING
WEIGHTS & MEASUREMENTS
Precise measurement of carat weight is important - slight differences can have a large impact on the value of a diamond. GCAL weighs diamonds on precise electronic balances according to international standards. This means that the weight is measured to the thousandth of a carat, and then is rounded to the hundredth of a carat. The electronic balances at GCAL are verified daily to ensure consistent and accurate results. The diamond is then measured by an optical scanning device that captures a series of high resolution images and creates an exact 3D model of every facet and angle, providing accurate geometrical measurements of the diamond. This proportion diagram appears on your GCAL certificate.
COLOR
Diamonds are color graded on a scale from D to Z. Each letter represents a slightly more saturated color. Your diamond is examined in a standard lighting environment and is compared to a set of Precision Master Color diamonds, which each have a precise color grade. Comparison of your diamond to the Precision Master diamonds continues until the color grade is determined. The difference between each color grade is very slight, but with experience, expert graders are able to consistently determine the accurate color grade of each diamond. GCAL utilizes a unique quality control procedure for grading the color and clarity of diamonds that assures the most accurate and consistent grading possible. At least three experienced gemologists examine and grade both the color and the clarity of every diamond. (After color grading, your diamond is checked for fluorescence, its reaction to ultraviolet light. A set of Master fluorescent diamonds is used to compare the strength of fluorescence. This intrinsic property is a permanent identifying characteristic of your diamond.)
CLARITY
Clarity is graded by examining your diamond under a microscope to assess internal and external characteristics such as crystals and feathers. A gemologist first inspects the diamond in the face-up position to find obvious inclusions. To find minute inclusions, the diamond has to be viewed through the pavilion as it is slowly rotated at least 3 full times, changing the viewing angle each time. The gemologist must assess the number, size, type, position and relief of each inclusion. After thorough inspection under the microscope, a 10x loupe is used to view the diamond in 4 different positions to determine the final clarity grade. GCAL utilizes a unique quality control procedure for grading the color and clarity of diamonds that assures the most accurate and consistent grading possible. At least three experienced gemologists examine and grade both the color and the clarity of every diamond.
RESEARCH
Before grading, every diamond is tested to confirm its origin - either natural earth mined or lab grown. If a diamond's origin cannot be verified by the initial spectroscopic analysis, then it is sent to the research department where additional more advanced tests are used to determine its authenticity. Considerable investment in state-of-the-art technologies has made GCAL one of the most well-equipped gem labs in the world. Once your diamond's origin is determined, it is ready for grading.
Photomicrograph
Photomicrographs are taken of the crown and pavilion of your diamond. These photos provide a forensic record of the exact appearance and condition of your diamond, and show internal and external characteristics visible at 10x magnification. Photographs are the most accurate way to illustrate the exact appearance and location of inclusions.
HEARTS & ARROWS
Hearts & Arrows is a term used to describe the patterns visible in perfectly faceted round brilliant cut diamonds when they are examined in specialized viewers. Through these viewers, it is possible to assess the alignment and consistency of every facet by looking at the equality of light return, or the hearts and arrows patterns.
A precisely faceted round brilliant diamond exhibits a pattern of eight arrows through the crown (top) side, and a pattern of eight hearts through the pavilion (bottom) side.
GCAL is the only laboratory that takes a real photograph of each diamond in the specialized viewer. This means that the images on your GCAL Certificate are actually of your diamond. Unlike the majority of the Hearts & Arrows photos printed on other lab reports or seen online, which are either generic sample images applied to every diamond or are computer generated - neither of which guarantees that the diamond you're paying a premium for is actually deserving of the term Hearts & Arrow.
OPTICAL BRILLIANCE
GCAL directly assesses the overall return of light to the viewer, called 'brilliance'.
The Optical Brilliance image is actually a digital photograph of the diamond taken in a special lighting environment that creates a strong contrast between the bright and dark areas. The image is then processed in a proprietary computer program that calculates the percentage of brilliance and the amount of light loss. This is a scientifically accurate and repeatable way to measure brilliance. The light gray areas of the image are facet outlines resulting from image processing to provide a realistic representation of the diamond's unique faceting.
In the Optical Brilliance Analysis image on the certificate, the white represents the light return and the blue represents areas of light loss. The light return is quantified based on measurable light return (aka - performance) and then graded as: Excellent, Very Good, Good, Fair or Poor.
Since the Optical Brilliance is measured by direct assessment, meaning that it is judged based on the way each diamond actually performs rather than a theoretical model, the brilliance image of each individual diamond will always look slightly different.
Brilliance is what gives a diamond its life, and what makes a diamond shine from across a room. Diamonds with a low percentage of brilliance look dull and dark.
OPTICAL SYMMETRY
The Optical Symmetry Analysis image is a digital photograph taken of each diamond in a special lighting environment that reveals the patterns of light return. All light returned at the same angles is represented by the same color. For example, all red areas represent light being returned within a consistent angle range. Therefore, the Optical Symmetry assesses the consistency of angles and alignment of facets by looking at the equality of light return.
Since the Optical Symmetry is measured by direct assessment, meaning that it is judged based on the way each diamond actually performs rather than a theoretical model, the symmetry images of each individual diamond will always look slightly different. Like the beauty and ever changing color patterns in a kaleidoscope, each diamond reveals its unique reflective pattern of symmetry. You can judge the cut of a diamond yourself simply by examining the symmetry image-the more even the pattern, the better the symmetry
PROPORTION DIAGRAM
Each diamond is measured by an optical scanning device that captures a series of high resolution images and creates an exact 3D model of every facet and angle, providing accurate geometrical measurements of the diamond. This proportion diagram appears on your GCAL certificate.
