Turquoise
Chemical Formula	CuAl6(PO4)4(OH)8·4H2O
Species	Phosphates
Crystal System	Triclinic
Mohs Scale	5-6
Specific Gravity	2.6-2.9
Color	bright blue, sky-blue, pale green, blue-green, turquoise-blue, apple-green, green-gray
Streak	Bluish white
Luster	Vitreous, Waxy, Dull
Refractive Index	n = 1.610 n = 1.615 n = 1.650
Diaphaneity	Transparent, Translucent, Opaque
Cleavage	Perfecton , good on
Fracture	Conchoidal
Crystal Habit：Massive, nodular
Geological Setting：Secondary mineral in potassic alteration zone of porphry copper deposits. Vein fillings in volcanic rocks and phosphate-rich sediments.