Aluminite

For the igneous rock type "websterite", see websterite.

Aluminite is a hydrous aluminium sulfate mineral with formula: Al₂SO₄(OH)₄·7H₂O. It is an earthy white to gray-white monoclinic mineral which almost never exhibits crystal form. It forms botryoidal to mammillary clay-like masses. It has a very soft Mohs hardness of 1–2 and a specific gravity of 1.66–1.82.