Sulfide
A sulfide is a mineral made of a metal combined with sulfur, such as troilite in meteorites.
A sulfide is a mineral in which a metal, usually iron or nickel, is joined to sulfur rather than oxygen. On Earth the best known is pyrite, or fool's gold. In meteorites the commonest sulfide is troilite, a simple iron sulfide that forms bronze-coloured grains and nodules.
Sulfides matter because sulfur behaves differently from silicate rock and metal. When an asteroid melted, iron sulfide mixed with molten metal and sank with it towards the core. That is why iron meteorites often contain big troilite nodules. In chondrites, small bronze sulfide grains sit beside metal flakes in the matrix and chondrules.
Other meteorite sulfides include pentlandite and pyrrhotite in carbonaceous chondrites, and exotic sulfides of calcium, magnesium, manganese and chromium in enstatite meteorites, which formed with so little oxygen that these normally reactive metals bonded to sulfur instead. On a cut face, sulfides look bronze, while metal looks silvery.
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Level: Explorer Ages 10 and up