Hemleyite
The iron-rich form of akimotoite: pyroxene composition packed into the ilmenite structure by shock.
Key facts
- Formula
- (Fe,Mg)SiO3
- Family
- High-pressure minerals
- Crystal system
- Trigonal
- First described
- the Suizhou L6 chondrite, 2017
Hemleyite was described in 2017 from the Suizhou L6 chondrite. It is named after Russell Hemley, an American physicist known for experiments at extreme pressures. It is known only from meteorites.
What it is
Hemleyite is an iron-rich silicate with the ilmenite structure, in which silicon is surrounded by six oxygen atoms instead of the usual four. It is the iron counterpart of akimotoite, which has more magnesium than iron. Both are made when pyroxene is squeezed to pressures like those about 600 kilometres down inside Earth.
Where it is found
It was found in the Suizhou L6 chondrite, inside shocked grains of iron-rich pyroxene next to a shock-melt vein, where the pyroxene was converted in the solid state.
How it is recognised
It is identified with transmission electron microscopy and diffraction, together with analyses showing that iron outweighs magnesium.
Did you know?
Hemleyite and hiroseite are both iron-rich forms of pyroxene from the same meteorite, with different structures.
Silicon surrounded by six oxygen atoms is typical of minerals from deep inside planets.