Calcite, CaCO3 (Calcium Carbonate), is one of the commonest minerals, being the main constituent of limestone. Calcite is often fluorescent, a small amount of Managnese is enough to make it glow red under UV light. The mineral will bubble in acid distinguishing it from many similar species, even other carbonates which do not dissolve so easily in cold acids.

Description: A brown matrix on top of which sits a thick carpet of blade-like Calcite crystals. The colour is ivory-white and many of the crystals have good terminations. Underneath is a mass of tiny snow-white crystals. In addition the matrix is richly studded by light green vesicles of Malachite. The green and white contrast is vary attractive.

Location: Nizhniy Tagil, Urals, Russia.