Suessite
An iron silicide formed in ureilites, where carbon stripped oxygen from silicates.
Key facts
- Formula
- (Fe,Ni)3Si
- Family
- Phosphides, carbides, nitrides and silicides
- Crystal system
- Cubic
- First described
- the North Haig ureilite, 1982
Suessite was described in 1982 from the North Haig ureilite, found in Western Australia. It is named after Hans Suess, who helped work out the abundances of the elements in the Solar System.
What it is
Suessite is a compound of iron and silicon. It forms when silicate is so strongly reduced that silicon enters metal. In ureilites, carbon is thought to have done the reducing, combining with oxygen and escaping as gas.
Where it is found
It occurs in the fine-grained rims of olivine grains in ureilites, along with tiny grains of iron metal formed in the same reaction.
How it is recognised
It is microscopic and identified by microprobe analysis.
Did you know?
Hans Suess and Harold Urey compiled a famous table of the abundances of the elements in 1956.
The reduced rims on ureilite olivine show that the parent body lost gas suddenly, probably when it was broken up.