Alabandite
Manganese sulphide, a characteristic mineral of the most oxygen-poor meteorites.
Key facts
- Formula
- MnS
- Family
- Sulphides
- Crystal system
- Cubic
What it is
Alabandite is manganese sulphide with the rock-salt structure. In meteorites it takes in a good deal of iron and magnesium, forming a series towards niningerite, magnesium sulphide. Its name comes from Alabanda, an ancient city in what is now Turkey.
Where it is found
It is a typical mineral of EL chondrites and aubrites, which formed in conditions so poor in oxygen that manganese joined sulphur instead. EH chondrites contain niningerite instead, which is one of the features that separates the two enstatite chondrite groups.
How it is recognised
In polished sections it is grey and slightly darker than troilite. Microprobe analysis gives its iron and magnesium content, which records the temperature at which the meteorite last equilibrated.
Did you know?
Alabandite alters quickly on Earth, so it is best preserved in freshly fallen meteorites.
Its rare cubic polymorph with the sphalerite structure, browneite, was first found in a meteorite.