This Specimen has been sold.
6.7" Quartz Crystal Cluster - Norway
This is a beautiful cluster of quartz crystals, most of which display phenomenal clarity. The crystals formed from a schist matrix that was collected from Hardangervidda, Norway. Along one edge, located towards the underside of the specimen, an aggregation of white adularia (variety of orthoclase) crystals can be found.
Silicon Dioxide, also known 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.
Adularia is a variety of feldspar that had the chemical formula KAlSi3O8. It's found most often as colorless to white aggregations within metamorphic rock, with one example being formation within cavities of crystalline schists. The crystals are commonly twinned, glassy and prismatic in structure, and in some cases they display opalescent characteristics. Adularia is very similar to orthoclase, even baring the same chemical formula, however it has a different crystalline structure and reacts differently to various tests.