It is an earthy white to gray-white monoclinic mineral which almost never exhibits crystal form.

It forms in clay and lignite deposits as an oxidation product of pyrite and marcasite along with aluminium silicates.

It occurs in association with basaluminite, gibbsite, epsomite, gypsum, celestine, dolomite and goethite.

[3] It is also known as alley stone, halite and websterite (named after Orcadian geologist Thomas Webster).

Aluminite is used by tile and masonry workers to reduce the setting time of mortars.