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Carat Weight: Refers to the standard unit of weight for diamond and other gemstones. Carat weight is measured at the GIA Laboratory using a highly precise electronic scale, rounded to the nearest hundredth of a carat.

Color: Refers to the GIA Color Scale, which extends from D (colorless) to Z (light yellow or brown). Color grades are established by comparing each diamond to a set of master comparison diamonds in a standard lighting and viewing environment. Each letter grade represents a range of color.

Clarity: Refers to internal features (inclusions) and surface characteristics (blemishes) within or on a diamond when viewed with 10x magnification under standard viewing conditions. The GIA Clarity Scale includes eleven clarity grades ranging from Flawless to I3.

Cut: Refers to how the proportions and finish of a diamond affect its overall appearance and quality. Cut is graded on a scale from Excellent to Poor and incorporates the diamond's brightness, fire, scintillation, weight ratio, durability, polish and symmetry. GIA  only provides a cut quality grade fro standard round and brilliant diamonds that fall within the GIA D-to-Z rangeProportions: Refers to a polished diamond's dimensions, facet angles and the relationships between them. For standard round brilliant diamonds, GIA reports the measurements of eight proportions; see diagram. For fancy shape diamonds (those other than the standard round brilliants), GIA reports measured values for table size and total depth. For all diamonds, girdle thickness and cutlet size are reported with word descriptions based on visual assessments.

Finish: Refers to the quality of a diamond's polish (the overall condition or smoothness of its surface), and its symmetry (exactness of its outline, and the shape, placement, and alignment of its facets). Polish and Symmetry are visually assessed and graded in one of the following categories: Excellent, Very Good, Good, Fair and Poor.

Fluorescence: Refers to the emission of visible light from a diamond when subjected to ultraviolet radiation. On GIA's diamond reports, fluorescence is a description, not a grade. The terms for describing the strength of fluorescence are: None, Faint, Medium, Strong and Very Strong. For Medium, Strong and Very Strong fluorescence, the color of the fluorescence will also be noted. A description of None refers to a range of fluorescence from indiscernible to very faint.

To learn more about GIA and its diamond grading reports, please visit

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