Diamond Grading The 4 “C’s”
The 4 C's, when referring to diamond value, are color, clarity, carat weight and cut. All four factors are equally important in determining the final cost of a diamond. The criteria for diamond grading, most respected internationally, was developed by the Gemological Institute of America (the G.I.A.). The terminology and systems described on this page, are those of the G.I.A.
Although many people think of gem quality diamonds as colorless, truly colorless diamonds are actually very rare. Most diamonds used in jewelry are nearly colorless with tints of yellow or brown. Color grades are determined by comparing each diamond to a master set. Each letter grade represents a range of color and is a measure of how noticeable a color is.
Fluorescence Some diamonds can emit a visible light when exposed to ultraviolet radiation, but fluorescence is not a factor in determining color or clarity grades. However, a description of its strength and color is provided on GIA Reports as an additional identifying characteristic..
Because diamonds form under tremendous heat and pressure, it is extremely rare to find a diamond that lacks any internal and external
characteristics. These characteristics are a by-product of its formation and help gemologists separate natural diamonds from synthetics and simulants, and identify individual stones.
A polished diamond’s beauty lies in its complex relationship with light. The magnificent display you see is made up of three attributes: Brightness is the combination of all white light reflecting from the surface and interior of a diamond. Fire describes the “flares” of colour emitted from a diamond. Scintillation describes the pattern of light and dark areas and the sparkle you see when the diamond, the light, or the observer moves. A diamond’s proportions affect its light performance, which in turn affects its beauty and overall appeal. Diamonds with fine proportions, symmetry, and polish optimize their interaction with light, and have increased brightness, fire, and scintillation.GIA assesses these factors for standard round brilliant diamonds in the D-to-Z colour range
For diamonds under one carat, each carat is
divided into 100 points – similar to pennies in a
dollar. 0.75 ct. = 75 points, 1/2 ct. = 50 points.
Beauty and Its Beholder
The 4Cs provide a way to objectively compare and
evaluate diamonds, but numbers alone can’t describe a diamond’s mysterious and captivating
beauty – for that, you’ll have to visit your local jeweler to see one for yourself.