5.5" Pyrite, Chalcopyrite, Quartz and Orpiment - Palomo Mine, Peru

Silicon Dioxide, also known as SiO2 or Quartz, is the second most abundant mineral in the Earth's crust. Quartz crystals generally grow in silica-rich, hot watery solutions called hydrothermal environments, at temperatures between 100°C and 450°C, and usually under very high pressure. Quartz veins are formed when open fissures are filled with hot water during the closing stages of mountains forming, and can be hundreds of millions of years old.

Orpiment a bright, orange to yellow arsenic sulfide mineral, whose name is derived from the latin phrase auripigmentum meaning “gold pigment” It is frequently found as a decay byproduct and in association with another arsenic mineral, realgar. Orpiment crystals are commonly found in dense groupings containing small, prismatic crystals, often with chisel-shaped or triangular pyramidal terminations.

Orpiment contains a significant amount of the poisonous mineral arsenic. While it’s not going to pose a health hazard sitting on a shelf, it’s recommended that you wash your hands after handling it.