Ahrensite
The iron-rich, spinel-structured form of olivine, the iron partner of ringwoodite.
Key facts
- Formula
- Fe2SiO4
- Family
- High-pressure minerals
- Crystal system
- Cubic
- First described
- the Tissint Martian meteorite, 2016
Ahrensite was described from the Tissint shergottite in the mid-2010s. It is named after Thomas Ahrens, an American geophysicist who studied shock waves in rocks.
What it is
Ahrensite has the chemistry of fayalite and the structure of ringwoodite. It is the iron end of the ringwoodite series and forms from iron-rich olivine at high pressure.
Where it is found
It occurs next to shock-melt pockets in the Tissint Martian meteorite, where olivine crystals partly changed to the denser form during the impact that ejected the rock from Mars.
How it is recognised
It is identified by electron microscopy and diffraction.
Did you know?
Ringwoodite and ahrensite are a pair, named after two scientists who studied the deep Earth and impacts.
The iron-rich spinel form had been made in laboratories since the 1950s.