Hiroseite
The iron-rich partner of bridgmanite: pyroxene composition in the perovskite structure.
Key facts
- Formula
- (Fe,Mg)SiO3
- Family
- High-pressure minerals
- Crystal system
- Orthorhombic
- First described
- the Suizhou L6 chondrite, 2020
Hiroseite was described in 2020 from the Suizhou L6 chondrite. It is named after Kei Hirose, a Japanese mineral physicist who studies Earth's deepest mantle. It is known only from meteorites.
What it is
Hiroseite has the perovskite structure of bridgmanite, the most abundant mineral in Earth's lower mantle, but contains more iron than magnesium. Making iron-rich perovskite in the laboratory requires enormous pressure, so its presence shows how intense the shock in Suizhou was.
Where it is found
It occurs in the Suizhou L6 chondrite as tiny grains that crystallised from a shock melt of pyroxene composition. When the pressure fell the perovskite was partly turned to glass, but some survived.
How it is recognised
It is identified by electron diffraction and analysis in a transmission electron microscope. Like bridgmanite, it tends to turn to glass under the electron beam.
Did you know?
Bridgmanite, its magnesium partner, makes up more of Earth than any other mineral, yet natural samples come only from meteorites.
It was one of several new high-pressure minerals reported from Suizhou in 2020 and 2021.