Elgoresyite
A dense magnesium–iron silicate with an unusual ratio of metal to silicon, found in a shock vein of the Suizhou chondrite.
Key facts
- Formula
- (Mg,Fe)5Si2O9
- Family
- High-pressure minerals
- Crystal system
- Monoclinic
- First described
- the Suizhou L6 chondrite, 2021
Elgoresyite was described in 2021 from the Suizhou L6 chondrite, which fell in China in 1986. It is named after Ahmed El Goresy, an Egyptian-born mineralogist who spent decades studying shocked meteorites. It is known only from this meteorite.
What it is
Elgoresyite contains five magnesium or iron atoms for every two silicon atoms, a recipe between that of olivine and of the oxides periclase and wüstite. Its atoms are arranged in the same way as in an iron oxide made in laboratories at very high pressure. Experiments suggest that minerals of this kind form at pressures found deep in Earth's lower mantle.
Where it is found
It was found as tiny grains in shock-melt veins about a third of a millimetre thick in the Suizhou L6 chondrite, together with ringwoodite, olivine, iron-nickel metal and glass rich in magnesium silicate.
How it is recognised
Its crystals are less than a micrometre across. It is identified by its composition, measured with an electron microprobe, and its structure, found by electron or X-ray diffraction.
Did you know?
Suizhou is the type meteorite for more than ten high-pressure minerals, more than any other rock from space.
Laboratory iron oxides with the same structure helped mineralogists recognise elgoresyite when it was found.