spene

Sphene, also known as titanite, is a calcium titanium cyclosilicate mineral. Its chemical formula is CaTiSiO5. It is known for its strong adamantine luster and often brilliant, prismatic crystals. Sphene is typically found in igneous rocks such as granite, syenite, and diorite, as well as in metamorphic rocks like gneiss and schist. It can also occur in skarns and contact metamorphic zones.

The color of sphene varies widely, ranging from colorless and pale yellow to brown, green, reddish-brown, and even black. This color variability is often due to the presence of trace elements, particularly iron. Sphene is relatively hard, with a Mohs hardness of 5 to 5.5. Its specific gravity is around 3.5.

Due to its high refractive index and dispersion, sphene can exhibit a noticeable "fire" similar to diamond, although its softness and rarity in gem quality limit its use in jewelry. It is more commonly found as accessory mineral in rock formations. Sphene is an important ore of titanium, although it is not a primary source. It is also of interest to mineralogists for its crystallographic properties and its occurrence in various geological settings, providing insights into the conditions under which these rocks formed.

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