Limonite has been used by people since prehistoric times. Their first use of limonite was probably as a pigment. It is found in many Neolithic pictographs, and throughout history it has been one of the most important pigments for creating paints in the yellow to brown color range known as ocher. Its use as a pigment…

Limonite usually occurs as a secondary material, formed from the weathering of hematite, magnetite, pyrite, and other iron-bearing materials. Limonite is often stalactitic, reniform, botryoidal, or mammillary in habit, rather than crystalline. It also occurs as pseudomorphs and coatings on the walls of fractures and cavities. Some limonite is found in stratified deposits where hydrous iron oxides form as…

Before modern mineral analysis, the name “limonite” was given to many of the yellowish to yellowish brown iron oxides produced during the weathering of iron-bearing rocks or deposited as bog, lake, and shallow marine sediments. Researchers who studied “limonite” discovered that it is amorphous and has a variable composition. It often contains significant amounts of…