Self-cut and polished Malachite Cabochon Gemstones from The Congo! This vivid green gem gets its color from copper. Malachite is invariably associated with copper ore deposits. It’s considered one of the minor copper ores, with 58% copper content. Its recovery is generally done, at least on the large scale, as a sidelight of copper mining.
Technically, malachite is a “secondary mineral,” which means it’s created by a chemical reaction between minerals that have already formed, rather than by a simple one-step process. Malachite may form when water containing carbon dioxide or dissolved carbonate minerals interacts with preexisting copper-containing rocks or when solutions containing dissolved copper minerals interact with carbonate rocks. Malachite’s characteristic swirling and concentric patterns are a result of this formation process. These bands reflect the waxing and waning of the solutions necessary for formation and the changes in their chemical content. Most commonly, the stone occurs in massive form as a microcrystalline aggregate, in lumps, or as crust on other rocks.