Kushiroite
An aluminium-rich pyroxene, long known only from laboratory experiments, found in refractory inclusions.
Key facts
- Formula
- CaAl2SiO6
- Family
- Silicates
- Crystal system
- Monoclinic
- First described
- the CH chondrite ALH 85085, 2009
Kushiroite was described in 2009 from refractory inclusions in the Antarctic CH chondrite Allan Hills 85085 and in other carbonaceous chondrites. It is named after Ikuo Kushiro, a Japanese petrologist. It is known only from meteorites.
What it is
Kushiroite is the calcium–aluminium pyroxene, often called Ca-Tschermak's pyroxene in laboratory work. It had been made in experiments for decades before it was found in nature.
Where it is found
It occurs in calcium-aluminium-rich inclusions in CH chondrites and in some other carbonaceous chondrites, where it formed in the hot environment near the young Sun.
How it is recognised
It is microscopic and identified with electron microprobe analysis and electron backscatter diffraction.
Did you know?
Geologists had used its formula for years when describing the chemistry of pyroxenes before anyone found the mineral itself.
CH chondrites are rich in metal and contain unusually small chondrules.