The 4 C’s of a Diamond
The Gemological Institute of America (GIA) supports a diamond color scale extending from D (colorless) to Z (light yellow or brown). Although many people think gem quality diamonds are colorless, a true colorless diamond is extremely rare. Most diamonds that are used in jewelry range from near colorless with slight amounts of yellow or brown. Color grades are assigned by comparing a diamond to an industry standard Master Set. The letters indicate how noticeable the color is.
Some diamonds have a degree of fluorescence, which is a visible light that appears when the stone is exposed to ultraviolet radiation, but it is not a factor in determining clarity grades, it is merely a characteristic of the diamond.
GIA recognizes 11 grades of clarity, ranging from Internally Flawless (IF) to heavily Included (I2). It is extremely rare to find a diamond that lacks any natural internal or external clarity characteristics.
The GIA cute scale ranges from Excellent to Poor. There are three factors in determining the quality of the cut. Brightness – the combination of all white light that is reflected from the surface and the interior of the diamond. Fire – the flashes of color emitted from the diamond. And Scintillation – the pattern of light and dark areas and the sparkle you see when the diamond is moved. The diamond’s proportions affect the light performance, which is really what makes the diamond beautiful. Diamonds that have fine proportions, symmetry and polish have increased brightness, fire and scintillation.
A one carat diamond weighs 200 milligrams. For diamonds less than a carat, each carat is divided into 100 points, for example .25 carat equals 25 points.