Titanium Dioxide Rutile occurs in nature as the well-known minerals rutile, anatase and brookite, and additionally as two high pressure forms, a monoclinic baddeleyite-like form and an orthorhombic α-PbO2-like form, both found recently at the Ries crater inBavaria. It is mainly sourced from ilmenite ore. This is the most widespread form of Titanium Dioxide Rutile -bearing ore around the world. Rutile is the next most abundant and contains around 98% Titanium Dioxide Rutile in the ore. The metastable anatase and brookite phases convert irreversibly to the equilibrium rutile phase upon heating above temperatures in the range 600–800 °C (1,112–1,472 °F).
The cotunnite-type phase was claimed by L. Dubrovinsky and co-authors to be the hardest known oxide with the Vickers hardness of 38 GPa and the bulk modulus of 431 GPa (i.e. close to diamond's value of 446 GPa) at atmospheric pressure.However, later studies came to different conclusions with much lower values for both the hardness (7–20 GPa, which makes it softer than common oxides like corundum Al2O3 and rutile TiO2) and bulk modulus (~300 GPa).
The oxides are commercially important ores of Titanium Dioxide Rutile . The metal can also be mined from other minerals such as ilmenite orleucoxene ores, or one of the purest forms, rutile beach sand. Star sapphires and rubies get their asterism from rutile impurities present in them.