Jade is actually two separate gems: nephrite and jadeite. In China, a pierced jade disk is a symbol of heaven.

• Mineral: Jadeite and Nephrite
• Chemistry: NaAlSi2O6 and Ca2(Mg,Fe)5Si8O22(OH)2
• Color:  Green, white, orange, yellow, lavender, black
• Refractive index: 1.666 to 1.680 (+/-0.008) and 1.606 to 1.632 (+0.009, 0.006)
• Birefringence:  Usually not detectable
• Specific gravity: 3.34 and 2.95
• Mohs Hardness: 6.5 to 7 and 6.0 to 6.5