Hematita

Hematita, or hematite, is an iron oxide mineral with the chemical formula Fe2O3. The name derives from the Greek haima, meaning blood, reflecting its distinctive reddish color. It is one of the most common minerals in Earth's crust and serves as a major source of iron ore.

Hematite forms in a variety of geological settings. It can be produced by the oxidation of iron-bearing minerals in soils and rocks, accumulate in hydrothermal veins, or occur as a weathering product in sedimentary environments, including banded iron formations. It exists in several physical forms, from earthy, ocherous masses to highly crystalline, metallic specimens known as specular hematite.

In terms of properties, hematite colors range from black or steel-gray in polished specimens to reddish-brown in the earthy variety. Luster varies from metallic to earthy; hardness is about 5.5 to 6.5 on the Mohs scale, and the mineral has a relatively high density around 5.26 g/cm3. The streak of hematite is reddish, and the mineral is weakly magnetic.

Uses and significance: hematite is an important iron ore, processed to produce iron and steel. It also has applications as a pigment (red ochre) and, in its specular form, is used in jewelry and decorative items. Hematite has notable scientific relevance beyond Earth; hematite-rich formations were identified on Mars, where they are considered potential indicators of past water activity.

Notes: the term hematita is used in several languages as the name for hematite; the mineral occurs in a wide spectrum of textures and forms, from earthy masses to shiny, plate-like crystals.