6.1" Sphalerite, Marcasite, Barite & Quartz Association - Missouri

This beautiful specimen contains an association of glimmering, iridescent druzy marcasite crystals, several deep red sphalerite "flowers", aggregations of white barite and a bed of quartz crystal druze from which the crystals formed. It comes from the Washington County Aggregates Quarry in the Potosi Barite District of Missouri.

Silicon Dioxide, also know 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.

Sphalerite is a part of the sulfides group and typically exhibits a grey/black appearance due to high concentrations of impurities. When sphalerite is in it's purest state, the chemical composition is ZnS, and can display a gemmy transparent light tan/yellow color. This is one of the few minerals that can form crystals ranging anywhere between gemmy and transparent to opaque and metallic-like. Opaque or cloudy sphalerite tends to be most abundant, due to the ease of iron replacing zinc in the process of formation.

Barite sometimes spelled Baryte (Barium sulfate) is well-known for its great range of colors and varied crystal habits. It is easily identifiable by its heavy weight, since most similar minerals are much lighter. It occurs in a large number of depositional environments, and is deposited through a large number of processes including biogenic, hydrothermal, and evaporation, among others

Sphalerite, Marcasite, Barite & Quartz
Washington County Aggregates Quarry, Potosi Barite District, Washington County, Missouri
6.1 x 3.6 x 3.9"