A New Book on Jadeite Jade

By Gary Roskin, G.G., FGA, Senior Editor -- JCK Online, 10/1/2003 2:00:00 AM

Jadeite Jade, A Stone and A Culture by Ou Yang, Chiu Mei, will enlighten everyone from the novice to the expert. It explains jadeite, its origins, trade terminology, the importance of jadeite varieties, and every enhancement (including acid and wax) and includes 200 beautiful color images.

For quality-grading jadeite, Ou Yang uses the "4C2T1V" principle. The "four Cs" are Color, Cut, Clarity, and Cracks. The "two Ts" are Transparency and Texture, and the "V" stands for Volume. In order of importance, they are listed as Color, Transparency, Texture, Cut, Clarity, Cracks, and Volume.

Color is divided into four key evaluating factors: purity, intensity (saturation), brightness, and evenness. As with other colored gems, the more pure the hue, the more important the gem. Green is more valued than bluish-green. In order of importance, the six categories of purity are: green, slightly yellowish-green, slightly bluish-green, yellowish green, bluish green, and grayish green. Yellowish green is second because it is said that yellow does not affect the gem's brightness; blue, on the other hand, will. Purity is extremely important to value, since, all else being equal, it can affect price by as much as 60% between green and bluish-green.

It's always been known that imperial jade should be transparent and pure green, but the illustrations of jadeite transparency are illuminating. For some, transparency is even more important than color. Factors that can affect transparency include thickness (greater thickness = less transparency), inclusions, and color (darker hue = less transparency).