Stishovite
A very dense form of silica, made by impacts, in which silicon is surrounded by six oxygen atoms.
Key facts
- Formula
- SiO2
- Family
- High-pressure minerals
- Crystal system
- Tetragonal
What it is
Stishovite is silica with the rutile structure, about 4.3 times as dense as water, compared with 2.65 for quartz. It was made in a laboratory by Sergey Stishov and colleagues in 1961 and found in nature at Meteor Crater the next year.
Where it is found
It occurs in rocks shocked by impacts at craters such as Meteor Crater and the Ries, and in the Chicxulub ejecta. It has been reported in some shocked Martian and lunar meteorites and in strongly shocked chondrites.
How it is recognised
It is identified by X-ray diffraction or Raman spectroscopy.
Did you know?
No ordinary geological process on Earth's surface makes stishovite, so finding it is strong evidence of an impact.
It forms at pressures above about 8 gigapascals.