What is jade?
'Jade', or yu, as it is called in China, is strictly speaking a generic term for two different gems, nephrite and jadeite. The name is derived from the Spanish 'piedra de ijada', loin-stone, jade having been recognised by the Amerindians as a remedy for kidney ailments. Because of its beneficial effect on the kidneys, the stone was also known as 'lapis nephriticus'. That, indeed, is where the term 'nephrite' came from.
Jadeite and nephrite are both regarded in China as 'zhen yu', 'genuine jade'. It was not until the beginning of the 19th century that mineralogists and gemmologists started to differentiate between them, since they bear a considerable resemblance to each other in terms of their appearance, their hardness and the properties they exhibit when being processed. Both are tough, since they consist of dense, close-grained, matted aggregates, but they differ from one another in their chemical composition and colours. Nephrite ranges mainly from mid to dark green or grey-green, but it can also be white, yellowish or reddish. Rarer, and somewhat tougher, jadeite displays hues which include green, but also white or pink, and reds, blacks, browns and violets. In both minerals, the way the colour is distributed varies a great deal. Only in the very finest jade is the colour evenly distributed. Both nephrite and jadeite often have veins, blemishes and streaks running through them, though these may not always be regarded as flaws. On the contrary, some of these patterns are considered particularly valuable.
Definition of Type Jade
A Jade (Natural Jadeite Jade)
Refer to natural jadeite which is not subjected to any form of chemical treatment except processes
such as colorless wax polishing are not defined as
on the crystalline structure of the jadeite jade, which has not been damaged.
B Jade (Jadeite jade has been artificially treated)
Refer to jadeite jade which is chemically treated and resin impregnated to enhance its translucency.
The structure of jadeite is damaged through this treatment and it will lose its lustre once the polymer deteriorates with the lapse of time.
In addition, "B" jade cannot withstand heat and pressure.
C Jade (Jadeite jade has been artificially dyed)
Jadeite of this kind is usually colorless or of very faint tone, and is therefore dyed to enhance its brightness.
However, such artificial hue will fade in time.
B + C Jade (Jadeite jade has been artificially treated and dyed)
Refer to Jadeite jade has been dyed to enhance its translucency and brightness during the chemically treated, resin impregnated process.
Note:jade are trade terms commonly used for Jadeite in the jade industry,
not represent the grades and class or the quality of jade.