Formation
(1) Metamorphic, formed by the transformation of calcium-aluminum silicates under conditions ranging from the green schist to the amphibolite facies.
(2) Hydrothermal, resulting from the alteration of calcium-rich plagioclases in igneous rocks.
(3) Metasomatic, as a major component of calc-silicate rock (skarn) in the contact zone between acidic intrusions and carbonate rocks.
