The 4 C's
If you find yourself in the market for a new diamond, it's wise to know what you are looking at before making the big purchase. The jewelry industry uses the 4 C's, a universal grading system developed by GIA (Gemological Institute of America), to determine the carat, color, clarity and cut of a diamond. Here's what you need to know.
1 Carat = 200 miligrams
1 Point = .01 carat = 1/100 of a carat
Diamonds that appear to be the same size does not mean they are the same weight. The proportions of the cut of the diamond will result in varying weights, effecting the price of a stone. When evaluating a diamond, we will measure the stone and weigh the stone.
The color of a diamond is another contributing factor to the rarity and ultimately the price of the diamond. Each end of the spectrum represents the most valuable diamonds based on color. A completely colorless diamond is rare. A vivid yellow or "fancy" diamond is also rare, and considered valuable for the depth of color. Most diamonds lie somewhere in the middle on the spectrum. A D-J diamond (assuming it has good cut and clarity), will be worth more than S-Y category with the same quality. Color is graded by a jeweler using a master set to compare the diamond's hue.
Diamonds are also available in blue, red, brown, pale green, and violet. These color variations occur when the diamonds are formed with traces of other minerals.
A diamond's clarity refers to the visibility of a diamond's flaws. Most diamonds have some sort of natural inclusion (blemish or flaw) although the visibility of the inclusion to the human eye varies. A diamond with VVS1 or VVS2 clarity, for example, would have inclusions so small that it could only be seen under magnification. Diamonds graded I1 or I2 would have inclusions that could be seen with the naked eye without magnification.
Clarity scale source: GIA
The cut of a diamond refers to the shape of the stone and the proportions in which the stone is cut. The cut of the diamond effects the stone's light performance, or the sparkle that is characteristic to a beautiful diamond. When cut correctly, light will enter the diamond and exit through the top of the diamond. If the stone is cut too shallow, then light will escape through the bottom of the stone. If cut too deep, light escapes through the sides.
Cut diagram: Stuller
Watch GIA's video on the 4 C's for further information.