Chenmingite
A dense form of chromite, made by shock, found in a Martian meteorite.
Key facts
- Formula
- FeCr2O4
- Family
- High-pressure minerals
- Crystal system
- Orthorhombic
- First described
- the Tissint Martian meteorite, 2017
Chenmingite was approved as a new mineral in 2017 from the Tissint Martian shergottite, which fell in Morocco in 2011. It is named after Ming Chen, a Chinese scientist who has studied high-pressure minerals in shocked meteorites. It has since been reported from other shocked meteorites.
What it is
Chenmingite has the same chemistry as chromite, iron chromium oxide, but its atoms are packed into a denser arrangement. It is one of two high-pressure forms of chromite found in meteorites; the other, xieite, has a slightly different structure and forms at even higher pressure.
Where it is found
It occurs as thin layers in chromite grains next to shock-melt pockets in the Tissint shergottite. Its presence shows that the impact that threw Tissint off Mars squeezed parts of the rock to very high pressures.
How it is recognised
It forms lamellae in chromite that are recognised by electron backscatter diffraction or transmission electron microscopy.
Did you know?
Pairs of minerals such as chenmingite and xieite act as pressure gauges for the impact that launched a meteorite.
Tissint is the type meteorite for several minerals, including tissintite and ahrensite.