Quartz
ID: 137
Quartz
Chemical Formula
SiO2
Hardness (Mohs)
7
Crystal System
Trigonal
Streak
White
Luster
Vitreous, greasy
Diaphaneity
Transparent, Translucent, Opaque
Color
Colorless, white, purple (amethyst), pink (rose quartz), brown (smoky quartz), yellow (citrine), green (aventurine), etc.
Crystal Habit / Mode of Occurrence
Prismatic crystals, massive, granular, cryptocrystalline (chalcedony).
Fun Facts
Quartz is the second most abundant mineral in the Earth's continental crust.