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.
HOW THE 4C'S AFFECT PRICE
The 4C's - carat weight, cut, color and clarity - are the foundation for assessing and valuating diamonds. Because diamonds are so precious and rare, any slight variation in carat, cut, color and or clarity will have a significant impact on price.
If you're diamond shopping then you probably already have a budget in mind. Of course you want to get the best diamond for your buck, but how do you decide the best combination of the 4C's? If you choose one color grade higher or lower on the scale, how will it affect your wallet? Read on.
The 4C's - How DIAMOND SHAPE affects value
The shape of a diamond affects the value because some shapes inherently yield a better weight retention percentage from the rough material. In other words, some shapes more closely follow the natural rough diamond form and therefore don't waste as much material during the cutting process. Faceted diamonds typically weigh 40%-60% of their original rough weight.
Supply and demand also play a part in how shape affects the value of a diamond. Rounds are the most popular and most costly shape. In addition, round brilliants require the most amount of skill and time to cut properly.
Generally speaking, when comparing diamonds of equal size and quality, rounds are the most expensive shape followed by Heart, Oval, Asscher, Pear & Marquise and then Emerald, Radiant, Cushion & Princess.
The price difference between rounds and princesses can be as little as 0-20% in lower colors and clarities, and as great as 100% in larger sizes and higher colors and clarities.
The 4C's - How CARAT WEIGHT affects value
Carat weight is the simplest value factor to understand. The larger the diamond, the more it costs, assuming all other factors are equal.
Per carat
Diamonds are priced on a per carat basis, which ranges greatly depending on the quality.
Calculate the price per carat to compare the cost of similar diamonds. Divide the selling price by the exact carat weight to determine the price per carat. For example, a 1.07 carat diamond that sells for $8,560 has a per carat price of $8,000 ($8,560 ÷ 1.07 = $8,000).
Exponential increases
Large diamonds are rarer than small diamonds; therefore, the price disproportionately increases as the carat weight increases. The cost of a 2-carat diamond is much greater than twice the cost of the same quality 1.00 carat diamond. A ring made of many small diamonds totaling 1-carat will most certainly cost less than a ring with a solitaire 1-carat diamond.
Price brackets
While diamond prices per carat go up exponentially compared to the weight, these increases occur in steps. This is because diamonds are traded on the wholesale level according to pricing guides that state per/carat values in weight ranges or brackets.
As an example, let's look at a the price of a 0.98ct vs. 1.02ct, both Round Brilliant H/VS2 Ideal Cut:
Per carat retail price for 0.90-0.99ct range is approx. $6,425, which makes the selling price of the 0.98ct = $6,296
Per carat retail price for 1.00-1.24ct range is approx. $7,590, which makes the selling price of the 1.02ct = $7,742
Big difference for something you can't see.
But buyer be warned, it's difficult to find diamonds that weight just below the price/carat step increase because cutters want to maximize the value of their goods.
The 4C's - How COLOR affects value It is difficult for an untrained eye to see the difference between each individual letter grade, but most people can easily see the distinction between diamonds of a few grade differences, such an E and an H or an H and a K, especially when compared side by side. Color differences are most noticeable when diamonds are next to one another. Keep this in mind when purchasing loose diamonds that will be set next to one another in a piece of jewelry. Make sure they are similar colors - not more than 2-3 grades different.
The price difference between each color grade (all else being equal) ranges from about 3% to more than 25%. The price increments increase when the other quality factors are higher. For example, the difference between each color grade for a 1.00 carat VS1 clarity diamond is about 10-15% per color grade, whereas the difference between each color grade for a 1.00 carat SI2 clarity diamond is about 3-7% per color.
Color is more noticeable in larger diamonds and in diamonds with fewer facets such as Emerald and Assscher cuts, and, color is less noticeable in well cut diamonds and in diamonds with more facets such as Round and Princess cuts.
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.
