Jade

Jade is best known as a green ornamental stone. Its colors varies from light to dark green, but it may also be other colors such as white, gray, and purple. Jade is actually the gemstone name for two different mineral forms, Jadeite and Nephrite. These two minerals can be identical in appearance and are similar in their physical properties, and until modern times no distinction was made between the two different types of Jade. While Nephrite is generally only green, cream, or white, Jadeite colors can range through the color spectrum with more exotic colors.

Chemical Formula	Nephrite: Ca2(Mg,Fe)5Si8O22(OH)2Jadeite: NaAlSi2O6
Color	White, Blue, Red, Green, Yellow, Orange, Brown, Pink, Purple, Gray, Black, Banded, Multicolored
Hardness	6Â -Â 7
Crystal System	Monoclinic
Refractive Index	1.60Â -Â 1.67
SG	2.9Â -Â 3.7
Transparency	Translucent to opaque
Double Refraction	-0.027 (Nephrite); 0.013 (Jadeite)
Luster	Waxy, vitreous
Cleavage	1 or 2,2 - prismatic. Due to lack of visible crystals, cleavage is rarely observed.
Mineral Class	Jadeite or Nephrite (Nephrite can be either Actinolite or Tremolite)