FeTiO3

FeTiO3, commonly known as ilmenite, is an iron titanium oxide mineral with the formula FeTiO3. It is the most important ore of titanium and a primary source of titanium dioxide (TiO2) pigment used in paints, plastics, and paper. In nature ilmenite occurs in a range of igneous and metamorphic rocks and as detrital grains in sedimentary deposits and beach sands.

Crystal structure and properties: Ilmenite crystallizes in the hexagonal system. Its structure comprises layers of edge- and corner-sharing octahedra formed by Fe2+ and Ti4+ in an oxygen lattice, with Fe and Ti occupying distinct octahedral sites. The mineral is typically opaque with a metallic to submetallic luster, gray to brownish-black color, and a high density around 4.7–5.0 g/cm3. Mohs hardness is about 5–6. It is weakly magnetic at room temperature.

Occurrence: Ilmenite is common in mafic to ultramafic rocks, such as basalts and peridotites, and in granitoids that host titaniferous magnetite. It also forms as an accessory phase in metamorphic rocks and is a common heavy mineral in sediments and placer deposits.

Etymology and production: The mineral was named after the Ilmen region in the Ural Mountains where it was first described. Economically, ilmenite concentrates are processed to produce TiO2 pigments, with additional, smaller-scale uses as a source of titanium metal after further processing.