Detailed information
Species
Roweite, Olshanskyite
Dimensions
24 x 37 x 27
mm
Weight
12 g
Locality
Shijiangshan mine Hexigten Banner, Chifeng City Inner Mongolia, China
Condition
No recorded repairs
Opened in 2008, Shijiangshan mine in Inner Mongolia, China has proven to be source of some of the world's best crystals of rare borate species as well as Type Locality to two new species. A lead-zinc mine, it is its unusual geological circumstances as a skarn deposit that has proved so fascinating to mineralogists. Roweite, a calcium manganese borate, was previously only known as microcrystals, but as evidenced by this superb miniature specimen, at Shijiangshan mine it forms significant highly visible clusters of fudge-coloured bladed, to scaly crystals. The individual platy crystals reach up to 5 or 6 mm in length, but align to produce much larger sprays. Often associated with Roweite is another extremely rare calcium borate, Olshanskyite, and on this sample it forms a partial overgrowth on one end of the Roweite crystals, as small radiating colourless prismatic crystals. This is one of the better specimens from the limited supply which appears to have come out during 2017 with very little seen since then. It is from the superb systematic collection assembled by the brothers Martin and Michael Günther (1951-2007 & 1956-2021).