Hematiit

Hematiit, commonly known in English as hematite, is an iron oxide mineral with the chemical formula Fe2O3. It is one of the most abundant minerals in Earth’s crust and is a principal source of iron ore. Hematiit forms in a variety of environments, including hydrothermal veins, sedimentary iron-oxide deposits, and the weathering products of iron-bearing rocks. It occurs worldwide and is an important ore mineral in countries such as Australia, Brazil, China, India, Russia, and the United States.

Physically, hematiit ranges in color from metallic steel-gray to deep reddish-brown in massive forms and can appear reddish to grayish in crystalline varieties. The mineral displays a characteristic red to reddish-brown streak and a metallic to earthy luster. It has a hardness of about 5.5 to 6.5 on the Mohs scale and a specific gravity around 5.0 to 5.3. Hematiit crystallizes in the hexagonal system and commonly occurs as tabular crystals, botryoidal masses, or earthy aggregates. Some specimens may show weak magnetic attraction due to trace magnetite, but hematite itself is not strongly magnetic.

There are two well-known varieties: specular hematite, which has a metallic luster and is often mirror-like, and earthy hematite, which is dull and earthy in appearance. Uses of hematiit include being a major source of iron for steel production, and historically as a red pigment (red ochre) in paints and cosmetics. The name derives from the Greek haima, meaning blood, referencing the mineral’s bright red coloration when powdered.

Overall, hematiit is a ubiquitous, economically important iron mineral with distinctive color, streak, and crystallography that aid in identification.