earthstory: Ruddy rutileThe most common form of titanium…
Ruddy rutile
The most common form of titanium dioxide was named after the Latin for red, due to the lovely deep hues exhibited by some specimens. It forms in both volcanic rocks and high temperature/high pressure metamorphic rocks, testament to the extreme conditions needed to distil it out of the Earth. It is also the most stable polymorph of TiO2. It is a common accessory mineral in plutonic rocks, magmas that never made it to the surface and cooled slowly in the crust when they reached their natural buoyancy point, though it sometimes occurs in lavas sourced deep in the mantle such as the (sometimes) diamond bearing kimberlites and lamproites. Some rutile is also formed by alteration of volcanic rocks.