This Specimen has been sold.
2.5" Smoky Quartz Crystal with Muscovite - Czech Republic
This smoky quartz specimen contains small muscovite crystals along some of the exterior of the quartz crystal. The quartz displays a milky coloration on its outside, with the interior (viewable from bottom of the specimen) clearly containing smoky quartz. This unique specimen was collected from the Czech Republic.
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.