websterite

Century Dictionary and Cyclopedia

1. n. In petrography, a phaneric, granular igneous rock composed of orthorhombic and monoclinic pyroxenes; a variety of pyroxenite.
2. n. Aluminite; hydrous tribasic sulphate of aluminium, found in Sussex, England, and at Halle in Prussia, in reniform masses and botryoidal concretions of a white or yellowish-white color.

Wiktionary

1. n. A hydrous aluminium sulfate mineral with formula Al2SO4(OH)4·7(H2O).

GNU Webster's 1913

1. n. (Min.) A hydrous sulphate of alumina occurring in white reniform masses.