7.9" Cabinet Sized, Gemmy Sphalerite On Quartz - China
Here is a beautiful 7.9" sphalerite & quartz crystal association, collected from China. Many of the sphalerite crystals formed in somewhat spherical aggregations and all display a fascinatng red-orange translucence. The specimen is in overall great shape and displays nicely on a flat surface, though a display stand will be accompanied with the specimen for preferred presentation.
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.
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.