Allite; Bauxitic Rock; Aluminous Rock
Bauxite is a chemical sedimentary rock that is rich in alumina and aluminosilicate minerals. In general, when bauxite contains over 40% Al2O3, and the Al2O3/SiO2 ratio is greater than 2.5, it is known as bauxite ore. Bauxite rock is similar to clay rock but is denser and harder. It has low plasticity and often has an oolitic or pisolitic texture and a blocky, botryoidal or grumose structure. It is sometimes in the form of a breccia aggregate with a clotted structure. It forms due to strong chemical weathering of aluminium silicate minerals, during which the alumina and kaolinite dissolve, are then transported to lower areas and deposited. It can also form by aquatolysis.