Home > Kalahari Manganese Field – March 18 > MS0915 Brucite, Sturmanite

Brucite, Sturmanite - Sold

Brucite is simple magnesium hydroxide. The mienral name honors Archibald Bruce (1777-1818), early American Mineralogist (Silliman, 1818). Sturmanite is a calcium manganese borate sulfate originally found in the Kalahari Manganese Field (Peacor et al. 1983). While the original description of sturmanite specifies the Black Rock mine as the type locality, later evidence suggests the type material actually came from the N'Chwaning II mine. On this specimen, brucite forms a botryoidal aggregate of pearly plates, with a 1.5 cm wide prominence on manganese oxide matrix. Nearby, but separate from the brucite is a single hexagonal tabular crystal of sturmanite, 7 mm across. Nice display specimen.