This Specimen has been sold.
2.6" Anatase (Titanium) Crystals On Adularia - Norway
This phenomenal specimen contains an association of 20+ metallic, twinned anatase crystals and adularia (variety of orthoclase). The crystals formed from a schist matrix that was collected from Hardangervidda, Norway. The largest anatase crystal on this specimen measures in at .65" long.
Anatase is composed of titanium dioxide, and typically forms dipyramidal crystals, although variations can occur with mineral clumping. Four pointed X-shaped anatase crystals, while rare, have been found and are known as "X-shaped penetration twins". Horizontal striations can be seen across most anatase mineral faces, with most crystals ending in points, or with variations of flattening on each end.
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.