Malachite
Malachite is a copper carbonate hydroxide mineral, usually in this striking green colour. The Hermitage Museum in St. Petersburg has a Malachite Room.
The origin of the name is uncertain; it may be from the Greek malachos, meaning soft, or it may be named for the green herb mallow.
I first came across this attractive gemstone in an open air market in Macau, where I purchased a small malachite elephant trimmed in gold, a piece of jewellery I later gave to my sister-in-law. This was many years ago.
Much later, I was astonished to learn that malachite can be dangerous. The copper-containing dust is toxic to breathe, and those who grind the stone are safest if they keep it wet to minimize this dust. They should also wear protective respiratory gear.
Malachite is about 58% copper and is often recovered as a by-product in copper mining; indeed, it is considered a minor copper ore. It is mined in the Congo, Russia, Namibia and the U.S.
According to the CFIA, the Canadian Food Inspection Agency, Malachite Green (MG) is used for the treatment of parasitic infections of fish, roe and shellfish. It is also an effective fungicide and is used to disinfect fish hatcheries. In Canada, it is approved for use in aquarium fish, but not for fish destined for human consumption.
Malachite green is also used as a dye in the textile and pulp and paper industries. This application is not new, however. Thousands of years ago in Egypt, malachite was ground and used as pigment.