Hydroxyapatite
Chemical Formula	Ca5(PO4)3(OH)
Species	Phosphates
Crystal System	Hexagonal
Mohs Scale	5
Specific Gravity	3.14-3.21
Color	Colorless, white, gray, yellow, yellowish green
Streak	White
Luster	Vitreous to subresinous, earthy
Refractive Index	nω = 1.651 nε = 1.644
Diaphaneity	Transparent to translucent
Cleavage	Poor on and
Fracture	Conchoidal
Crystal Habit：As tabular crystals and as stalagmites, nodules, in crystalline to massive crusts