Like Diamonds, the evaluation of Jadeite is based upon four important criteria:
Colour is the top contributing aspect in a piece of jade. The colour is measured by saturation, brilliance, evenness and purity of the stone. The most valuable jadeite, known as “Fei Cui” 翡翠 or Imperial Jade, is hued in a rich emerald green colour with a high level of translucency.
Clarity relates to the existence and visual appearance of internal characteristics called inclusions. These may be crystals of a foreign material or structural imperfections that can appear whitish or cloudy. The number, size, colour and visibility of inclusions can all affect the relative clarity of the gem.
Nature Inclusions
Translucency is the degree to which light can penetrate the stone and is measured by what is called “shui fen” 水份 or moisture content. The more translucent the jade, the more valuable it is. This translucence must be present despite the thickness of the jade. Jade that are cut ‘egg shell’ thin is translucent simply because it is thin enough for light to pass through, and is extremely fragile. Highly translucent jadeite is a rarity.
Eggshell
Texture refers to the fineness of the crystal grains within the jade. The best jadeite has an extremely fine texture. The jadeite matter must be of an intricate and consistent texture, before sufficient light can pass through the cabochon to maximise the light reflection.
LEFT : Nature Jadeite Veins RIGHT : Nature Crack.
Thickness must be proportionate to the size of the jade to ensure the strength of the jade, and should not be ‘egg shell’ thin. Many people are often under the impression that the value of the jade cabochon lies very much on the height in the dome of the cabochon. A piece of jade with a high dome will not have much collection value if it does not possess all of the above three criteria.
The classic cabochon cut is the most unforgiving shape for jadeite as it provides a thorough view of any imperfections in the jadeite rather than concealing the natural flaws in the stone; thus, only the best jadeite is used for cabochons.
Type A-Jade
Untreated Jadeite is often referred to as A-Jade, however this term also applies to Jadeite which has been polished and then sometimes covered in colourless wax. This wax conceals near-surface cracks and improves surface lustre. It is not a permanent treatment.
Type B-Jade B-Jade is Jadeite Jade of low-quality colour and translucency which has been bleached in acids to remove impurities, then filled with synthetic resins which make it harder. The Jadeite then resembles better-quality, brighter Jadeite. This treatment is damaging to the gem, and can be difficult to detect.
Type C-Jade Often, pale Jadeite is dyed, either green or lilac. Dyed material is referred to as C-Jade. Many pieces of Jadeite Jade are both bleached, dyed and filled with resins, resulting in B+C Jade.
