6.2" Polished Quartz Bowl - Madagascar
This is a 6.2" wide, polished quartz bowl from Madagascar. This specimen has been polished into a large bowl, from a larger chunk of quartz.
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.