DIAMOND AND COLORED GEMSTONE EDUCATION

A GIA Diamond Grading Report™ not only provides expert analysis of  carat weight ,  color ,  cut  and  clarity , it also contains a plotting diagram that clearly shows a diamond’s inclusions and clarity characteristics. All GIA reports contain security features such as a hologram, security screen and microprint lines that prevent them from being forged or duplicated.  Gem owners around the world have sought out GIA reports because of their scrupulous and impartial evaluation. Diamond merchants recognize that stones bearing GIA reports have instant credibility in the marketplace. Those who buy, sell or curate the world’s most important diamonds, including the legendary Hope and the De Beers Centenary, rely on GIA.

A GIA Diamond Grading Report™ not only provides expert analysis of carat weight, color, cut and clarity, it also contains a plotting diagram that clearly shows a diamond’s inclusions and clarity characteristics. All GIA reports contain security features such as a hologram, security screen and microprint lines that prevent them from being forged or duplicated.

Gem owners around the world have sought out GIA reports because of their scrupulous and impartial evaluation. Diamond merchants recognize that stones bearing GIA reports have instant credibility in the marketplace. Those who buy, sell or curate the world’s most important diamonds, including the legendary Hope and the De Beers Centenary, rely on GIA.

The GIA Diamond Grading Report includes an assessment of a diamond’s 4Cs –  color ,  clarity , cut, and carat weight – along with a plotted diagram of its clarity characteristics and a graphic representation of the diamond’s proportions. For standard round brilliant cut diamonds falling in the D-to-Z color range, the report also includes a GIA Cut grade.

The GIA Diamond Grading Report includes an assessment of a diamond’s 4Cs – color, clarity, cut, and carat weight – along with a plotted diagram of its clarity characteristics and a graphic representation of the diamond’s proportions. For standard round brilliant cut diamonds falling in the D-to-Z color range, the report also includes a GIA Cut grade.


The 4- C’s: Color, Cut, Clarity, and Carat

COLOR   The diamond color evaluation of most gem-quality diamonds is based on the absence of color. A chemically pure and structurally perfect diamond has no hue, like a drop of pure water, and consequently, a higher value. GIA’s D-to-Z diamond color-grading system measures the degree of colorlessness by comparing a stone under controlled lighting and precise viewing conditions to master stones of established color value.  Many of these diamond color distinctions are so subtle that they are invisible to the untrained eye; however, these distinctions make a very big difference in diamond quality and price.

COLOR

The diamond color evaluation of most gem-quality diamonds is based on the absence of color. A chemically pure and structurally perfect diamond has no hue, like a drop of pure water, and consequently, a higher value. GIA’s D-to-Z diamond color-grading system measures the degree of colorlessness by comparing a stone under controlled lighting and precise viewing conditions to master stones of established color value.

Many of these diamond color distinctions are so subtle that they are invisible to the untrained eye; however, these distinctions make a very big difference in diamond quality and price.


CUT   Diamonds are renowned for their ability to transmit light and sparkle so intensely. We often think of a diamond’s cut as shape (round, heart, oval, marquise, pear), but a diamond’s cut grade is really about how well a diamond’s facets interact with light. A diamond’s cut is crucial to the stone’s final beauty and value. And of all the diamond 4Cs, it is the most complex and technically difficult to analyze.  To determine the cut grade of the standard round brilliant diamond – the shape that dominates the majority of diamond jewelry – GIA calculates the proportions of those facets that influence the diamond’s face-up appearance. These proportions allow GIA to evaluate how successfully a diamond interacts with light to create desirable visual effects such as:   Brightness:  Internal and external white light reflected from a diamond   Fire:  The scattering of white light into all the colors of the rainbow   Scintillation:  The amount of sparkle a diamond produces, and the pattern of light and dark areas caused by reflections within the diamond  The Cut Grades range from Excellent, Very Good, Good, Fair, and Poor.

CUT

Diamonds are renowned for their ability to transmit light and sparkle so intensely. We often think of a diamond’s cut as shape (round, heart, oval, marquise, pear), but a diamond’s cut grade is really about how well a diamond’s facets interact with light. A diamond’s cut is crucial to the stone’s final beauty and value. And of all the diamond 4Cs, it is the most complex and technically difficult to analyze.

To determine the cut grade of the standard round brilliant diamond – the shape that dominates the majority of diamond jewelry – GIA calculates the proportions of those facets that influence the diamond’s face-up appearance. These proportions allow GIA to evaluate how successfully a diamond interacts with light to create desirable visual effects such as:

Brightness: Internal and external white light reflected from a diamond

Fire: The scattering of white light into all the colors of the rainbow

Scintillation: The amount of sparkle a diamond produces, and the pattern of light and dark areas caused by reflections within the diamond

The Cut Grades range from Excellent, Very Good, Good, Fair, and Poor.


CLARITY   Natural diamonds are the result of carbon exposed to tremendous heat and pressure deep in the earth. This process can result in a variety of internal characteristics called ‘inclusions’ and external characteristics called ‘blemishes.’  Evaluating diamond clarity involves determining the number, size, relief, nature, and position of these characteristics, as well as how these affect the overall appearance of the stone. While no diamond is perfectly pure, the closer it comes, the higher its value.  The GIA Diamond Clarity Scale has 6 categories, some of which are divided, for a total of 11 specific grades.   Flawless (FL)  No inclusions and no blemishes visible under 10x magnification   Internally Flawless (IF)  No inclusions visible under 10x magnification   Very, Very Slightly Included   (VVS1  and  VVS2)  Inclusions so slight they are difficult for a skilled grader to see under 10x magnification   Very Slightly Included (VS1  and  VS2)  Inclusions are observed with effort under 10x magnification, but can be characterized as minor   Slightly Included (SI1  and  SI2)  Inclusions are noticeable under 10x magnification   Included (I1 ,  I2 , and  I3)  Inclusions are obvious under 10x magnification which may affect transparency and brilliance

CLARITY

Natural diamonds are the result of carbon exposed to tremendous heat and pressure deep in the earth. This process can result in a variety of internal characteristics called ‘inclusions’ and external characteristics called ‘blemishes.’

Evaluating diamond clarity involves determining the number, size, relief, nature, and position of these characteristics, as well as how these affect the overall appearance of the stone. While no diamond is perfectly pure, the closer it comes, the higher its value.

The GIA Diamond Clarity Scale has 6 categories, some of which are divided, for a total of 11 specific grades.

Flawless (FL) No inclusions and no blemishes visible under 10x magnification

Internally Flawless (IF) No inclusions visible under 10x magnification

Very, Very Slightly Included (VVS1 and VVS2) Inclusions so slight they are difficult for a skilled grader to see under 10x magnification

Very Slightly Included (VS1 and VS2) Inclusions are observed with effort under 10x magnification, but can be characterized as minor

Slightly Included (SI1 and SI2) Inclusions are noticeable under 10x magnification

Included (I1, I2, and I3) Inclusions are obvious under 10x magnification which may affect transparency and brilliance


CARAT   Diamond carat weight is the measurement of how much a diamond weighs. Each carat can be subdivided into 100 ‘points.’ This allows very precise measurements to the hundredth decimal place. A jeweler may describe the weight of a diamond below one carat by its ‘points’ alone. For instance, the jeweler may refer to a diamond that weighs 0.25 carats as a ‘twenty-five pointer.’ Diamond weights greater than one carat are expressed in carats and decimals. A 1.08 carat stone would be described as ‘one point oh eight carats.’   All else being equal, diamond price increases with diamond carat weight because larger diamonds are more rare and more desirable. But two diamonds of equal carat weight can have very different values (and prices) depending on three other factors of the diamond  4Cs :  Clarity ,  Color , and  Cut .  It’s important to remember that a diamond’s value is determined using all of the 4Cs, not just carat weight.

CARAT

Diamond carat weight is the measurement of how much a diamond weighs. Each carat can be subdivided into 100 ‘points.’ This allows very precise measurements to the hundredth decimal place. A jeweler may describe the weight of a diamond below one carat by its ‘points’ alone. For instance, the jeweler may refer to a diamond that weighs 0.25 carats as a ‘twenty-five pointer.’ Diamond weights greater than one carat are expressed in carats and decimals. A 1.08 carat stone would be described as ‘one point oh eight carats.’


All else being equal, diamond price increases with diamond carat weight because larger diamonds are more rare and more desirable. But two diamonds of equal carat weight can have very different values (and prices) depending on three other factors of the diamond 4Cs: Clarity, Color, and Cut.

It’s important to remember that a diamond’s value is determined using all of the 4Cs, not just carat weight.


GIA CERTIFIED GEMSTONES

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While renowned for its diamond grading expertise, GIA also receives a vast array of colored gemstones for identification. Over the decades, the Institute has created a database of information on more than 100,000 individual colored gemstones. Using this database and sophisticated analytical tools, GIA can pinpoint a gem’s identity and, depending on the gemstone, its geographic origin. GIA also identifies synthetics, simulants and stones that have undergone treatment. A particularly important activity is determining whether a gemstone’s color is natural or the result of a treatment process.

GIA’s processes for evaluating colored stones involve the same item identification and tracking procedures used in diamond grading.