Formation
(1) Magmatic, formed by primary crystallization as an accessory mineral from titanium-rich, calc-alkaline melts (particularly syenites, diorites, and granites).
(2) Metamorphic, formed by the transformation of titanium-bearing phases (such as ilmenite or rutile) in calcium-rich rocks under amphibolite to granulite facies conditions.
(3) Hydrothermal, by precipitation in fractures (Alpine type) or as a product of the alteration of titanium-bearing minerals
