Formula: Cu4(SO4)(OH)6

Colour: Green, emerald green, green-black, light green; bluish green in transmitted light.

Lustre: Vitreous, Pearly

Hardness: 3½ – 4

Specific Gravity: 3.97

Crystal System: Monoclinic

Name: Named in 1824 by Serve-Dieu Abailard “Armand” Lévy in honor of the French geologist and mineralogist, André-Jean-François-Marie Brochant de Villiers [1772-1840].

Type Locality: Mednorudyanskoye Cu Deposit, Nizhnii Tagil, Sverdlovsk Oblast – Russia

A common secondary copper hydroxy sulphate. May be observed as pseudomorphs after malachite, azurite and langite, and altered to chrysocolla. Closely related to the less common antlerite.