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
The Clay Minerals Society The primary purpose of The Clay Minerals Society is to stimulate research and to disseminate information relating to all aspects of clay science and technology. Through its conferences and publications, the Society offers individuals a means of following the many-sided growth of the clay sciences and of meeting fellow scientists with widely different backgrounds and interests. The primary activities of The Clay Minerals Society consist of publication of the bi-monthly journal "Clays and Clay Minerals", organization of the annual conference, workshop, and field trip, student research grants, publication of a workshop lecture series, slide sets, and special publications, the providing