A diamond’s “cut” grading measures whether a stone has maximum brilliance and sparkle– it’s what brings fire to the ice and catches your eye. Cut is different from the shape of the diamond (e.g., princess cut, emerald cut, etc.). The cut evaluation rates the diamond’s angles and brilliance, evaluating the diamond’s proportion, facet arrangement and overall workmanship quality. Diamond cut grades range from “excellent” to “poor” with the excellent rating resembling the ideal cut illustrated below.
Virtually all diamonds for sale today include minor irregularities or imperfections, although these imperfections are rarely visible to the naked eye. The minor imperfections in a diamond are caused by the liquid volcanic rock in which a diamond is created. While diamonds are primarily pure carbon, during the crystallization process, other nearby minerals may become trapped within the cooling mass, which in turn affects the diamond’s clarity.
Clarity is measured on a scale with grades running from “flawless” (virtually no imperfections) to “included” (imperfections heavily included). “Pure” diamonds are flawless or internally flawless; these diamonds are exceedingly rare and expensive. VVS-1 and VVS-2 grade diamonds have very, very small inclusions; VS-1 and VS-2 diamond have very small inclusions; SI-1 and SI-2 diamonds have small inclusions; and I-1, I-2 and I-3 diamonds are heavily included. Diamonds are graded under a 10X magnifying glass in good lighting by an experienced grader. The final grade is determined by how easily the grader can see the inclusions and blemishes.
The “color” rating actually refers to the absence of color in a diamond. Like a drop of pure spring water, when it comes to diamonds, the less color, the better. The jewelry industry recognizes the highest quality gemstones by purity of hue. In order to demine the absence or presence of different hues, an experienced diamond grader will compare the diamond to “master stones” using artificial or natural northern daylight. Colorless diamonds are graded either D, E or F. Near colorless diamonds are graded G, H, I or J. Slightly tinted diamonds receive a K, L, M or N rating. Very light yellow diamonds are graded O, P, or Q; light yellow diamonds are graded R, S, or T; yellow diamonds receive a U, V or W grading and light fancy diamonds are graded X, Y or Z.
The most well-known of the four C’s, “carat” is the unit of measurement for ta diamond’s weight. A carat is subdivided into 100 “points”; for example, a 50-point diamond is “half a carat” or “0.5 ct”. Today, many individuals also equate carat with size. Generally speaking, the higher the carat weight, the larger (and more expensive) the stone. However, color, clarity and cut also affect a diamond’s price; two diamonds of equal carat weight may have very different prices due to these three ratings.