6.4" Fuchsite Included Quartz Crystals on Muscovite - Peru

Quartz is the name given to silicon dioxide (SiO2) and is the second most abundant mineral in the Earth's crust. Quartz crystals generally grow in silica-rich environments--usually igneous rocks or hydrothermal environments like geothermal waters--at temperatures between 100°C and 450°C, and usually under very high pressure. In either case, crystals will precipitate as temperatures cool, just as ice gradually forms when water freezes. Quartz veins are formed when open fissures are filled with hot water during the closing stages of mountain formation: these veins can be hundreds of millions of years old.

Muscovite is a phyllosilicate mineral of aluminium and potassium. It has a highly perfect basal cleavage, yielding remarkably thin laminæ that are often highly elastic. It can be colorless or tinted through grays, violet, or red, and can be transparent or translucent. Fuchsite and mariposite are green varieties of muscovite, owing their green color to chromium impurities. Alurgite is a manganese-bearing, purple to reddish variety of muscovite.