Brochantite is a sulfate mineral. It is formed in arid climates or rapidly oxidizing copper sulfide deposites. It is named after a French geologist and mineralogist, A. J. M. Brochant de Villiers.
The crystals are usually small and are prismatic or acicular in habit. They are transparent to translucent, with a vitreous luster, and are of an emerald-green to blackish green colour.
The limonite is covered with a velvety mass of emerald-green acicular crystals. The crystals are fine and are grass like. It is about 4.5 to 2.5 inches and weights 13.8 oz.