Mineral Species: Wolframite on Rhodochrosite

Chemical Formula: (Fe,Mn)WO3

Chemical Name: Iron Manganese Tungstate

Mineral Class: Tungstate

Mineral Notes: Wolframite is actually a series between two minerals; Huebnerite and Ferberite. Huebnerite is the Manganese rich end member while Ferberite is the iron rich end member. Wolframite is the name of the series and the name applied to all specimens intermediate between the two end members. Most specimens found in nature fall within 20 - 80% range of the series and these are termed Wolframites. Only if they are more pure than 80% manganese are they called Huebnerite and conversely if they are 80% iron they are called Ferberite.

Description: Well-defined, upright, tabular crystals of Wolframite on Rhodochrosite. The crystals cluster together into attractively coloured dark grey aggregates against the pink matrix of the Rhodochrosite. The effect is very striking and aesthetic.

Location: Cavnic, Maramures, Romania.