Jadeite


	Define Jade Jade refers collectively to two different minerals --- Jadeite and Nephrite. Most Jade of gem value is Jadeite Burmese Jade. Most valuable is the Imperial Jade, an emerald green transparent jadeite from Burma. In Academic Terms Jadeite and Nephrite have different physical and chemical characteristics:

	Nephrite	Jadeite
Chemical composition	Ca2(Mg, Fe)5Si6O22(OH)	NaAISi2O6
Mineral composition	Amphibole Group	Pyroxene Group
Crystalline structure	fibrous	micro-granular
Hardness	6-6.5	6.5-7
Specific gravity	2.9-3.1	about 3.33
Refractive index	1.62	1.65-1.66
Polished surfaces	Smooth with a waxy sheen	Hard and lustrous
Color	Evenly distributed; translucent white, dark green, black	Spotty or clustered distribution; white, grey, green

In China, where jade has been treasured the most, there was only
nephrite before the 18th century. The highly treasured pieces from that
time are creamy white in color and uniformly translucent.
Since the mid-18th century, jadeite has been imported from Burma
(now Myanmar), and has become the most popular form of jade
in China. Besides in Burma, jadeite is also found in Japan, part of the
former Soviet Union, Central America, and California. The actual color
and the texture of the jadeite piece derives from the metallic element(s)
it contains and the way the piece was formed geologically.
Green jadeite, known as fei tsui in Chinese, seems to be used almost
exclusively in jewelry-setting, and is the most popular type of jadeite.