geothite

Goethite is an iron oxide mineral with the chemical formula FeO(OH). It is a common component of rocks and soils and is found in various geological environments. Goethite is one of the most important iron ores, alongside hematite and magnetite. It crystallizes in the orthorhombic system and is typically found as botryoidal masses, fibrous aggregates, or earthy coatings. The color of goethite ranges from yellow to brown and black, depending on the presence of impurities.

Goethite is a significant mineral for several reasons. It serves as a primary ore for iron production, and its presence in soils can indicate periods of weathering and oxidation. In some cases, it forms as a secondary mineral, resulting from the alteration of other iron-bearing minerals like pyrites or siderite. Goethite is also known for its use as a pigment, historically employed in paints and cosmetics due to its natural coloring properties.

The mineral can be found in a wide variety of locations worldwide, often associated with sedimentary rocks, bogs, and iron-rich springs. Its formation is typically linked to the oxidation of iron-containing solutions, commonly in the presence of water. The stability of goethite under surface conditions contributes to its widespread occurrence. While not a particularly hard mineral, its abundance and economic importance make it a subject of interest in geology and industry.