Ilmeniitti

Ilmeniitti, also known as ilmenite, is an iron titanium oxide mineral with the chemical formula FeTiO3. It is the most common titanium oxide mineral and an important source of titanium. The mineral is named after Lake Ilmen in Russia. It crystallizes in the trigonal (rhombohedral) system and typically forms black to dark gray crystals or grains.

Physically, ilmenite is black to brownish-black with a metallic to submetallic luster. It has a hardness of about 5–6 on the Mohs scale and a specific gravity around 4.7–5.0. The streak is gray to black. In rocks, ilmenite often occurs as coarse to fine-grained grains and may show exsolution features with hematite, creating titanomagnetite textures in some samples.

Geologically, ilmenite is common in mafic to ultramafic igneous rocks such as basalts and gabbros, where it can be a primary accessory mineral. It also appears in metamorphic rocks and is a major constituent of heavy mineral sands, where it contributes to beach and placers deposits. Associated minerals commonly include magnetite, hematite, rutile, and titanite.

Economically, ilmenite is a principal ore of titanium. It is mined and processed to produce titanium dioxide pigments, which are used in paints, plastics, and paper, among other products. In some regions, high-grade ilmenite concentrates are selectively processed to extract titanium metal or other titanium-bearing minerals. Overall, ilmenite plays a key role as a feedstock in the titanium industry.

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