Rutile
Titanium dioxide, a minor mineral of chondrites and achondrites, and the parent of shock forms.
Key facts
- Formula
- TiO2
- Family
- Oxides
- Crystal system
- Tetragonal
What it is
Rutile is the most common form of titanium dioxide, a hard, dense mineral with a very high refractive index. Its name comes from the Latin for reddish. Squeezed by shock, it changes to dense forms such as riesite.
Where it is found
It occurs as tiny grains with ilmenite and chromite in ordinary chondrites, in some refractory inclusions of carbonaceous chondrites, in eucrites and in lunar rocks. In meteorites it often forms by the breakdown of ilmenite or chromite during heating.
How it is recognised
It is identified by its composition and by Raman spectroscopy, and appears brightly in backscattered electron images.
Did you know?
White paint, sunscreen and toothpaste all owe their whiteness to titanium dioxide.
Rutile needles cause the star in star sapphires.