Malachite Malachite Malachite is a copper carbonate hydroxide mineral, with the formula CuCO(OH). This opaque, green banded mineral crystallizes in the monoclinic crystal system, and most often forms botryoidal, fibrous, or stalagmitic masses, in fractures and spaces, deep underground, where the water table and hydrothermal fluids provide the means for chemical precipitation. Individual crystals are rare but do occur as slender to acicular prisms. Pseudomorphs after more tabular or blocky azurite crystals also occur. The stone's name derives (via , , and Middle English "melochites") from Greek Μολοχίτης λίθος "molochitis lithos", "mallow-green stone", from μολόχη "molōchē", variant of μαλάχη "malāchē", "mallow".
Malachite for decorative purposes, such as in the Malachite Room in the Hermitage Museum, which features a huge malachite vase, and the Malachite Room in Castillo de Chapultepec in Mexico City. "The Tazza", a large malachite vase, one of the largest pieces of malachite in North America and a gift from Tsar Nicholas II, stands as the focal point in the centre of the room of Linda Hall Library. Malachite has also been used on the base of the FIFA World Cup Trophy. A 17th-century Spanish superstition held that having a child wear a lozenge of malachite would help them sleep,