Item talk:Q41948
From geokb
Mindat Description
A medium-temperature metasomatic rock characterized by the presence of quartz and white mica, commonly with topaz, fluorite, tourmaline and locally with amazonite, orthoclase, andalusite and diaspore
Geoscience Ontology Description
Greisen is a class of endoskarn, formed by self-generated alteration of a granite. Greisens appear as partly coarse, crystalline granite, partly vuggy with miarolitic cavities, disseminated halide minerals such as fluorite, and occasionally metallic oxide and sulfide ore minerals, borate minerals (tourmaline) and accessory phases such as sphene, beryl or topaz.
