A copper-containing silicate of variable, and often uncertain, composition, chrysocolla has been used as an ornamental material since the antiquity. The cyan-colored mineral is often found in close association with its better-known copper-containing counterparts, namely azurite, turquoise and malachite, with these four materials together comprising the green and blue “Eilat stone” of ancient Israel. When intergrown with the much harder quartz, chrysocolla forms a significantly more durable, rare and valuable gemstone known as “chrysocolla chalcedony” or “gem silica”.
Chrysocolla is usually encountered in the form of veins, crusts and botryoidal, or “grape-like”, masses within the exposed oxidation zones of copper deposits. The most significant of these are located within Israel, DR Congo (Zaire), Chile, Mexico, Russia, Peru and the United States (Arizona), with the latter two localities also producing the valuable, quartz-containing material described above.