Quartz
Chemical Formula	SiO2
Species	Silicates
Crystal System	Trigonal
Mohs Scale	7
Specific Gravity	2.59-2.65
Color	colorless, brown, black, Purple, red, green, yellow
Streak	White
Luster	Vitreous
Refractive Index	n = 1.543 - 1.545 n = 1.552 - 1.554
Diaphaneity	Transparent, Translucent
Cleavage	Poor/IndistinctThe rhombohedral cleavage r is most often seen, there are at least six others reported.
Fracture	Conchoidal
Crystal Habit：6-sided prism ending in 6-sided pyramid (typical), drusy, fine-grained to microcrystalline, massive
Geological Setting：Most of them...