Brochantite
Chemical Formula	Cu4SO4(OH)6
Species	Sulfates
Crystal System	Monoclinic
Mohs Scale	3-4
Specific Gravity	3.97
Color	Green, emerald green, or black
Streak	Pale green
Luster	Vitreous, Pearly
Refractive Index	n = 1.728 n = 1.771 n = 1.800
Diaphaneity	Transparent, Translucent
Cleavage	PerfectOn perfect.
Fracture	Irregular/Uneven, Conchoidal
Crystal Habit：Prismatic crystals; acicular needle-like crystals; druse
Geological Setting：In arid climates or in rapidly oxidizing copper sulfide deposits under low acid conditions.