IV. Class of Minerals

Oxide minerals are natural compounds of metals or metalloids with oxygen, often occurring as accessory (secondary) minerals in igneous and metamorphic rocks or as detrital (transported) grains in sediments. They are relatively hard and dense and are resistant to wear. Hydroxide minerals contain a hydroxide anion group, generally appearing secondarily as products of weathering, and are of lower hardness and density. Many oxide and hydroxide minerals are ore minerals or components of well-known ores such as bauxite and limonite, from which economically important metals are extracted.