2.6" Selenite Encrusted Rosasite and Aurichalcite Clusters - Mexico

Selenite is a variety of gypsum, a soft sulfate mineral composed of calcium sulfate dihydrate (CaSO4 · H2O). When chemically pure, gypsum is transparent and colorless, but impurities give the gypsum a diverse range of colors and formations. Desert rose selenite and satin spar are just a few of the varieties of gypsum known to have formed though hydrothermal processes.

Aurichalcite (chemical formula (Zn,Cu)5(CO3)2(OH)6) is a secondary mineral that forms in the oxidation zones of copper and zinc ore deposits. It often forms as radiating, fuzzy-looking acicular blue-green crystals and linings along cavity walls.

Rosasite is a secondary mineral that forms in oxidation zones of copper-zinc deposits, generally forming a fibrous botryoidal sphere that can appear vitreous and silky. While typically featuring a blue-green color, colorless specimens are not unheard of. The chemical formula of rosasite is CuZnCO3(OH)2.