Muscovite from Brazil, on black 2016-base

The mineral muscovite is a hydrated aluminum-potassium-fylosilicaat having the chemical formula KAl2 (AlSi3) O10 (OH) 2. Is a muscovite mica, a fylosilicaat with a plate structure consisting of a layer of SiO4 tetrahedra which share all of their neighbors, three oxygen atoms. Thus, they form a flat network of hexagonal rings. In these layers, the binding is particularly strong, the bond between the layers is, however, much less strong, so that the material easily into thin, often cleaving is transparent layers. In the crystal structure is a complex stacking of the layers is possible, which leads to several poly types, variants of the crystal structure. Virtually all polytypes of muscovite are monoclinic, but also rare trigonal accumulations occur. Chemistry: in muscovite are a series of isomorphous replacements for, with the most common one for K: Na, Rb, Cs, Ca, Ba, NH4 For octahedral Al: Mg, Fe2 +, Fe3 +, Mn, Li, Cr (green variant fuchsiet), Ti, V For OH: F muscovite is one of the most common micas, and it comes in a wide variety of rocks before, but mainly in felsic igneous rock, such as granite. Mica is sometimes used as a refractory material, for example as windows in a stove. Also, as a carrier material for scanning probe microscopy, it is sometimes used because it is a clean surface that is atomically flat upon cleavage. That is, the roughness of the surface lies in the order of ångströms.

 
Muskovite