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Diamond Knowledge

Each Diamond has specific qualities that establish its value.

A GIA Diamond Grading Report gives you comprehensive understanding of those qualities.

The 4Cs of Diamond Quality, Color, Clarity, Cut, and Carat Weight, is the universal method for assessing the quality of any diamond over the world.

GIA is not only a global authority, but the world's trusted source for unbiased assessment.


Carat

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.'

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 masterstones stones of established color value.

Cut

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

GIA's diamond cut grade also takes into account the design and craftsmanship of the diamond, including its weight relative to its diameter, its girdle thickness (which affects its durability), the symmetry of its facet arrangement, and the quality of polish on those facets.

The GIA Diamond Cut Scale for standard round brilliant diamonds in the D-to-Z diamond color range contains 5 grades ranging from Excellent to Poor.

Clarity

GIA diamond clarity standards, is divided into six types, 11 grades.

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