Feldspar Feldspar Feldspars (KAlSiO – NaAlSiO – CaAlSiO) are a group of rock-forming tectosilicate minerals that make up about 41% of the Earth's continental crust by weight. Feldspars crystallize from magma as veins in both intrusive and extrusive igneous rocks and are also present in many types of metamorphic rock. Rock formed almost entirely of calcic plagioclase feldspar (see below) is known as anorthosite. Feldspars are also found in many types of sedimentary rocks. The name "feldspar" derives from the German "Feldspat", a compound of the words "Feld", "field", and "Spat", "a rock that does not contain ore". The change from
Museum of Minerals in Siófok Museum of Minerals in Siófok Mineral Museum (Hungarian: Ásványmúzeum) is a museum in Siófok, Hungary. It was opened in 1986 in the centre of the city. It is a private museum, but the State also takes care of the collection. It includes more than 3000 pieces. It includes examples most notably from the Carpathian basin, and most of them are minerals and fossils. There are a lot of very rare minerals from the mining areas of Transylvania. There are some objects from distant regions of the world as well. The Kövecses Family has been collecting minerals for 4 generations. The