Biotite, coarse

The magnetic black generic compound biotite (named in honour of the 19th century French physicist and mineralogist Jean-Baptiste Biot) belongs to the group of sheet silicate. Together with muscovite, this dark magnesia-iron-glimmer is the most common among the mica group. Biotite is a very common rock-forming mineral found in schists, gneises, granites and rhyolites, often in association with quartz, potassic feldspars, plagioclase, nepheline, muscovite and others. Biotite flakes can be split up into very thin, highly translucent sheets. When pulverized, filtered, and carefully washed biotite makes a beautiful brown color with a brilliant golden luster. In Europe, biotite is found mostly in the Ore Mountains east of Prísecnice (near the German-Czech border), in the Hrubý Jeseník Mountains, the Owl Mountains, in Alsace near Saine-Marie-aux-Mines and in Norway. Other important sources for biotite are Canada and India. The biotite from Kremer Pigmente comes from Canada.