Tissintite
A high-pressure, calcium-rich pyroxene formed by shock from feldspar in a Martian meteorite.
Key facts
- Formula
- (Ca,Na)AlSi2O6
- Family
- High-pressure minerals
- Crystal system
- Monoclinic
- First described
- the Tissint Martian meteorite, 2015
Tissintite was described in 2015 from the Tissint shergottite, which fell in Morocco in 2011. It is named after the meteorite and the village near which it fell.
What it is
Tissintite is a pyroxene with calcium, aluminium and silicon in which some metal sites are empty. It formed when calcium-rich plagioclase was squeezed by the shock of the impact that launched the rock from Mars.
Where it is found
It occurs within shock-melted plagioclase in Tissint, and has since been reported in other shocked Martian and lunar meteorites.
How it is recognised
It is microscopic and was identified by electron diffraction and Raman spectroscopy.
Did you know?
Tissint was seen to fall as a fireball in July 2011 and is one of only a handful of witnessed Martian meteorite falls.
Minerals like tissintite show that the rocks were shocked to roughly 25 gigapascals when they left Mars.