Gibbsite is an important ore of aluminium in that it is one of three main phases that make up the rock bauxite.

Gibbsite has three named structural polymorphs or polytypes: bayerite (designated often as α-Al(OH)3,[2]: 2  but sometimes as β-Al(OH)3)[citation needed], doyleite, and nordstrandite.

The sheets are only held together by weak residual bonds and this results in a very soft easily cleaved mineral.

However the lower charge in brucite's magnesium (+2) as opposed to gibbsite's aluminium (+3) does not require that one third of the octahedrons be vacant of a central ion in order to maintain a neutral sheet.

[5] The lattice parameters for gibbsite depending upon the particular method used to measure or calculate them and are therefore displayed as ranges below.