Diamond Grading Terminology A diamond's cost is based on the characteristics known as the "4 C's". Clarity, Color and Cut (proportion) are the quality elements which together with the Carat Weight determine the value of a stone. The closer a diamond grades to the left of one or all of these scales the rarer and the more costly it will be. While clarity is frequently assumed to be the most important factor of all the "C's", in fact, color and cut (especially cut) have a more profound affect on the visual appearance of a diamond. Clarity A diamond's clarity is determined by the number, nature, position, size and color of internal characteristics called "inclusions" and surface features called "blemishes". These irregularities occurred in the liquid magna (volcanic rock) within which the diamond was created. Diamonds are mostly pure carbon, however, during crystallization other minerals nearby, or even other bits of carbon forming more quickly may have become trapped within the cooling mass. These show themselves as the various characteristics which make up the clarity of a diamond (included crystals, feathers, clouds etc). Clarity is measured on a scale ranging from pure (flawless) to heavily included (I-3). The clarity of a diamond is graded by using 10X magnification under good lighting by an experienced grader. The final clarity grade is usually determined by how easy the inclusions and blemishes are for the grader to see. Color Ideally, a diamond should have no color at all, like a drop of spring water. Increasing degrees of body color are measured on a scale ranging from no color at all (D) to deeply colored (Z). Beyond "Z" is the range where the diamond's color is vivid and rich, called "fancy colors". Diamonds of known color are used as comparison stones for color grading. Grading is done by comparing the diamond to be graded against these "master stones" under either artificial or natural north daylight (in the Northern Hemisphere). A machine called the "Colorimeter" can be used for color grading but there is no substitute for the trained human eye. Cut Cut, sometimes the forgotten "C", ensures that a given stone has maximum brilliance and sparkle which would not be the case were the stone cut for weight alone.We use the following scale to grade a stone on it's overall appearance. Angles and percentages are for diamond cutters and graders. Simply put, when looking at a diamond, if it doesn't catch your eye or if it doesn't flash in the light, it's probably not well cut. Good cutting is what brings fire to the ice.