Borates are a complex group of approximately 150 minerals, containing Boron and Oxygen in combination with metals. About 80 of them also contain water. Others contain Hydroxyl ions (OH) 1-, or halogens, especially Chlorine.

They are an important group of industrial minerals which can be divided into two sub-groups. The first are primary in origin, created by igneous activity in an environment almost totally lacking water. Examples include Ludwigite and Paigeite. They are rare. The second group, the hydrous Borates, form in arid conditions from the evapouration of surface solutions. Examples include Ulexite and Colemanite. They are commonly called evapourite deposits and are important sources of Borax, an important industrial material.

The fundamental building block of borates is a Boron atom surrounded by three Oxygen atoms in the same plane, (BO3) 3-. This Borate triangle, like the Silica tetrahedron, can form an almost infinite variety of chains, rings and sheets by sharing oxygen atoms. This property gives Borate minerals very similar structural variations to those found in the Silicates and explains the large number of mineral species. However only about five minerals can be said to be common, the rest are highly exotic species. Most Borates are soft, but a few are extremely hard. A handful of the artificially produced anhydrous Boron compounds are amongst the hardest substances known.