Malachite: Gemstone Information
Malachite: Gemstone Information Malachite is Cu2(CO3)(OH)2 and occurs as acicular to prismatic or thick tabular monoclinic crystals but these are too small to be used as ornaments. Botryoidal masses or stalactitic malachite is plentiful. The masses are a deep saturated green and show characteristic banding;the hardness is 3.5–4.5 and there is one direction of perfect cleavage.The SG is usually just over 4 and the RI of the massive material is 1.85.Malachite occurs as a common secondary mineral in the oxidation zone of copper ore deposits and can be an ore of copper. From the ornamental point of view the most productive deposits include large pure masses formerly (Anthony et al., 2003) from mines around Nizhni Tagil and Ekaterinburg, Ural Mountains, Russia and from various deposits in Africa, including especially mines in Katanga Province, Congo.Crystals from Tsumeb. Namibia.Malachite occurs frequently with azurite (q.v.) and the name azurmalachite has been used for intimate combinations. Pseudomalachite is Cu2 3(PO4)2(OH)4 and is found in association with malachite; it may have been used ornamentally as the hardness is higher than that of malachite at 4.5. Malachite is also found in association with the copper silicate chrysocolla and they may be fashioned together.