Description | This 10 cm tall sample, from an unknown location, contains conspicuous turquoise-blue malachite, Cu2(CO3)(OH)2, with yellow-brown and red-brown limonite (a rusty mix of various iron hydroxides and oxides). Clear calcite crystals, CaCO3, have grown into some of the open spaces. Malachite is a pretty mineral, and some specimens are semi-precious gemstones. It often precipitates in vugs forming layers of different colors, as in this photograph. Individual crystals are rare. Malachite is commonly found with other beautiful minerals, including azurite and chrysocolla. |