Malachite: the Beautifal Rust

     Malachite is a green mineral that is formed by the chemical weathering of copper; basically it is copper rust. If you have ever watched a piece of copper turn orange, then brown, and then green you have witnessed the formation of the mineral malachite. The malachite that people find in the ground is formed the same way and often grows on top of natural copper deposits. This malachite often forms in layers and can eventually become quite thick. When malachite of this nature is cut open a certain way it looks like a green agate with bands that alternate between light and dark green. The layers of malachite may be of varying hues, but its color does not alter: all malachite is green. In addition to forming as a rust on copper, malachite can also be found as nodules, botryoidal aggregations, and stalactites, as well as monoclinic crystals. A lot of monoclinic crystals that I have seen look like two keys from a keyboard that are fused at the base so that the face that has the letter on it is visible on both keys. I have never seen malachite with individual monoclinic crystals, so I cannot tell you what it looks like. Malachite is opaque (light does not pass through it) and it is often found with azurite, which is another copper mineral.
     Malachite has been used as a copper ore for some time and still serves as one today, but it is not used as often as other ores since malachite is also a decorative stone. Malachite’s banding makes it a popular stone to polish for such applications as cabochons, slabs, and boxes as well as carvings. It is used to make jewelry, but its polish will scratch very easily as it is very soft. Malachite can also be crushed to make pigment.
     Malachite can be found wherever copper is mined or exposed to the air (you can probably find malachite under your sink if your pipes are slightly corroded) Some places where malachite can be found in the ground and in the rocks are Arizona, Russia, Zaire, and Namibia.
     Malachite is one of the fastest-forming minerals that I know of. Simply place a piece of copper outside, let it get rained on a little, and you’ll have malachite growing after a little while. It might seem strange to say it, but rust can be beautiful!