titanitebearing

Titanite, also known as sphene, is a calcium titanium cyclosilicate mineral with the formula CaTi(SiO4)O. It is a common accessory mineral in many igneous rocks, particularly those that are silica-undersaturated and rich in titanium, such as alkaline igneous rocks, syenites, and nepheline syenites. Titanite is also found in metamorphic rocks like skarns, gneisses, and schists, often forming as a secondary mineral. Its occurrence in these diverse geological settings highlights its stability over a range of temperatures and pressures.

The mineral typically crystallizes in the monoclinic crystal system, forming wedge-shaped or prismatic crystals. Titanite is known for its adamantine to resinous luster and can exhibit a wide range of colors, including yellow, brown, green, black, and red. Its refractive index is high, contributing to its brilliance, and it possesses a notable dispersion, often referred to as "fire," similar to that of diamond, especially in well-formed crystals. This optical property has led to its use as a gemstone, although its relative softness and cleavage limit its durability for everyday wear.

Titanite plays a role in geochronology, as certain isotopes of uranium, thorium, and lead can substitute into its crystal structure, allowing for radiometric dating of the rocks in which it is found. It is also a source of titanium and calcium. The presence of titanite in a rock can provide clues about the geological history and conditions of its formation.