2.5" Azurite, Calcite and Rosasite Association - Utah

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.

Calcite, CaCO3, is a carbonate mineral and the most stable polymorph of calcium carbonate. The other polymorphs are the minerals aragonite and vaterite. Calcite crystals are trigonal-rhombohedral, though actual calcite rhombohedra are rare as natural crystals. However, they show a remarkable variety of habits including acute to obtuse rhombohedra, tabular forms, and prisms. Calcite exhibits several twinning types adding to the variety of observed forms. It may occur as fibrous, granular, lamellar, or compact. Cleavage is usually in three directions parallel to the rhombohedron form.

Azurite is a copper carbonate hydroxide mineral best known for its beautiful and vibrant blue appearance. Azurite typically forms in nodular formations with other colorful, copper-rich minerals. It is a secondary mineral that precipitated in pores, crevices, and caverns from water with high concentrations of carbon dioxide.

Azurite and malachite are known to form in union with each other since their chemical makeup is very similar. In fact, the presence of more or less water in the location of formation is enough to determine whether an abundance of malachite over azurite, or vise-versa, will accumulate.