Greifensteinite is beryllium phosphate mineral with formula: Ca₂Fe²⁺₅Be₄(PO₄)₆(OH)₄·6H₂O. It is the Fe²⁺ dominant member of the roscherite group.Roscherite group on Mindat.org
/ref> It crystallizes in the monoclinic crystal system and typically forms prismatic dark olive green crystals. It was first described in Germany at Greifenstein Rocks,

Ehrenfriedersdorf Ehrenfriedersdorf () is a town in the district of Erzgebirgskreis, in Saxony, Germany. It is situated 8 km northwest of Annaberg-Buchholz, and 21 km south of Chemnitz. Theatre At the start of the 1990s the folk theatre, the ''Mundartth ...

, and was named for the location. At the type locality, it occurs within a lithium-rich

pegmatite A pegmatite is an igneous rock showing a very coarse texture, with large interlocking crystals usually greater in size than and sometimes greater than . Most pegmatites are composed of quartz, feldspar, and mica, having a similar silicic com ...

miarolitic Miarolitic cavities (or ''miarolitic texture'') are typically crystal-lined irregular cavities or vugs most commonly found in granitic pegmatites, and also in a variety of igneous rocks. The central portions of pegmatites are often miarolitic as th ...

cavities. It was approved by the

International Mineralogical Association Founded in 1958, the International Mineralogical Association (IMA) is an international group of 40 national societies. The goal is to promote the science of mineralogy and to standardize the nomenclature of the 5000 plus known mineral species. Th ...

in 2002.

References

{{Reflist *Rastsvetaeva R K, Gurbanova O A, Chukanov N V (2006) Crystal structure of greifensteinite Ca₂Fe²⁺☐Mg₂Fe²⁺₂Be₄(PO₄)₆(OH)₄·6H₂O. Doklady Chemistry 41, 18-2

Phosphate minerals Beryllium minerals Calcium minerals Monoclinic minerals Minerals in space group 15