Lhématite

Lhématite is a mineral composed of iron(III) oxide, with the chemical formula Fe2O3. It is one of the most common iron-bearing minerals and is a principal ore of iron. Lhématite occurs in a variety of forms, including massive, botryoidal, oolitic, and earthy. Its color ranges from steel-gray to black to brownish-red. The red color is characteristic and is responsible for the red color of many soils.

The name lhématite comes from the Greek word for blood, referring to its often blood-red streak. It forms in a wide range of geological environments, including sedimentary, metamorphic, and igneous rocks. Lhématite is relatively hard, with a Mohs hardness of 5 to 6. It is not soluble in acids but can be dissolved in concentrated sulfuric acid.

Historically, lhématite has been used as a pigment, particularly for red ochre. It has also been used as a weighting agent in drilling muds and as a source of iron. In more recent times, its primary importance lies in its role as an iron ore. Large deposits of lhématite are found in many parts of the world, including Australia, Brazil, China, and India. The extraction and processing of lhématite are crucial to the global steel industry. Its presence on Mars has also been a key indicator in the search for evidence of past water.