7.8" Smoky Quartz Cluster - Brazil
This is a cluster of smoky quartz crystals from Brazil. The entire plate is 7.8 inches wide and the longest point is just over 2.5 inches long. The crystals on the specimen are relatively small, however, nearly all of the crystals are damage free and have beautiful smokey coloration. It has not been heated or treated to change the natural color.
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.
Smoky quartz is a grey-brown to black variety of quartz. This common name is derived from from the appearance of smoke within the quartz crystal. Dependent on the location and the chemicals present during formation, smoky quartz can appear opaque black, however it’s typically translucent to some extent. It’s believed that the quartz gains this color from a combination of natural irradiation and aluminum impurities.