Wiktionary
rambergite
n. (context mineralogy English) A hexagonal-dihexagonal pyramidal mineral containing manganese and sulfur.
Wikipedia
Rambergite
Rambergite is a manganese sulfide mineral with formula Mn S.
It has been found in anoxic marine sediments, rich in organic matter of the Gotland Deep, Baltic Sea and also in skarn in the Garpenberg area, Dalarna, Sweden. It was named after the mineralogist, Hans Ramberg (1917–1998).
It is closely related to Hauerite.