Browneite
A rare cubic form of manganese sulphide with the sphalerite structure.
Key facts
- Formula
- MnS
- Family
- Sulphides
- Crystal system
- Cubic
- First described
- the Zakłodzie meteorite, 2012
Browneite was approved as a new mineral in 2012 from the Zakłodzie enstatite-rich meteorite of Poland. It is known only from meteorites.
What it is
Browneite has the same composition as alabandite, manganese sulphide, but the sphalerite structure instead of alabandite's rock-salt structure. In the laboratory this form is unstable and changes to alabandite when heated, so browneite must have formed quickly at relatively low temperature.
Where it is found
It occurs as tiny grains with buseckite and other sulphides in Zakłodzie, an ungrouped meteorite rich in enstatite.
How it is recognised
It is identified by electron backscatter diffraction, which separates it from the more common alabandite.
Did you know?
Manganese sulphides are common only in enstatite meteorites, which formed with almost no oxygen.
Browneite was described by the same team that found buseckite.