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 CLARITY
4C's - Clarity
Few diamonds are perfect. Given their enormously violent birthing process in volcanoes millions of years ago, most diamonds have tiny remnants of their beginning or intruder minerals inside them. Thankfully, most of these inclusions, as they're called, are hidden from sight. It takes magnification to see them.
A clarity grade is an evaluation of the degree to which a diamond is free of blemishes and inclusions. Inclusions can be thought of as natural birthmarks on a diamond. Since no two diamonds have exactly the same inclusions, this property can also be described as an identifying characteristic.
How are diamonds clarity graded?
Grading diamonds for clarity is a process of hunting down microscopic imperfections and rating them for difficulty of discovery. The more difficult it is to find inclusions under 10x magnification- using a binocular microscope- the higher the clarity grade. Once these specks are found, their number, size, and location all play a role in deciding the clarity grade. Read more about Clarity Grading
What is the best clarity of a diamond?
Gemologists use an 11-grade scale - from 'FL' (Flawless), the highest, to 'I3', very noticeable inclusions - to grade clarity. Each grade down represents increased ease of detection. In short, grades stand for degrees of visibility.
Diamonds with no discoverable imperfections under 10x magnification earn a FL (flawless rating). If there is an oh-so-slight surface imperfection, it gets an IF (internally flawless) grade.
Next comes the VVS (very, very slightly included) grades, in which there are two, and the difference between them has to do with whether an inclusion is extremely difficult - VVS1, or merely very difficult - VVS2, to see.
Once the difficulty factor is reduced, diamonds receive grades of either VS 1-2 (very slightly) or SI 1-2 (slightly) included. If this sounds like gemological nit-picking, keep in mind that degrees of perceptibility can make enormous value differences.
Finally, there comes a point at which inclusions become noticeable to the naked eye. Diamonds with visible inclusions receive one of three I (included) grades. See Photomicrographs of each Clarity Grade
How do I know my diamond was graded correctly?
When buying diamonds, especially ones that have been mounted, always ask for a diamond certificate. Some manufacturers and retailers hide visible inclusions under prongs. You want a diamond that has no hidden surprises.
Make sure your diamond comes with a Grading certificate from a respected gemological laboratory, such as GCAL. GCAL is an independent laboratory, not affiliated with any jewelers, and has the consumers' best interests in mind. Read more about GCAL's Standards
Clarity grading is a subjective scientific procedure that depends on the skill and experience of the grader and reasonable variances are possible, but every effort is made to eliminate bias. GCAL utilizes consensus grading methodology and an exceptional quality control procedure to assure the most accurate, objective and consistent grading possible. Before GCAL gives a diamond its quality grades, each stone is individually examined by two experts and verified by a third senior expert. Every diamond is weighed, measured, examined, tested and photographed several times before a certificate is issued.
Is it worth the money to buy a diamond with higher clarity? This is a personal decision. If perfection is your style, then consider a diamond graded VS1 or higher. If you want a diamond at a good value without any inclusions visible under normal conditions, then consider a diamond graded VS2, SI1 or SI2. If you want big flash for little cash, then consider a diamond graded I1, I2 or I3.
At what point can inclusions be seen with the naked eye? Several factors influence which inclusions you can see with your naked eye - the quality of your vision, the lighting, the angle of view, the cut of the diamond. Generally speaking, diamonds graded SI1 and higher do not have eye-visible inclusions. Diamonds graded SI2 and I1 may or may not have inclusions that are visible without magnification. I2 and I3 diamonds have visible inclusions that even a bat can see.
Should I be concerned that a diamond with inclusions is a weaker diamond? No, except with diamonds graded I2 or I3, in which case durability becomes a concern. Diamonds graded I1 or higher are not 'weakened' by their inclusions.
Diamonds are not indestructible. Diamonds are the hardest natural material and can only be scratched by another diamond, but they can break if struck too hard. Read more About Diamonds
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.
