Emery is a fine-grained mix of minerals that has historically been used as an abrasive. One common use is in emery boards, which are used to gently file nails and calluses on the body. It is also embedded in emery cloth, and added to a variety of compounds and surfaces to increase traction. This mineral is available in pure form for people who want to make their own abrasive blends, and it is also available in an assortment of formats designed for specific uses, like emery paper for enhancing traction on stairs.
The blend of minerals used varies. The key ingredient is corundum, an extremely hard mineral, and the mix typically includes an assortment of iron-bearing minerals such as magnetite as well. Depending on the mineral blend, emery can be dark gray to almost black in color, with a gritty texture which can be adjusted through grinding.
Historically, emery has been heavily produced on the Greek island of Naxos, as well as in Turkey. Other abrasives have since replaced it, including blends of synthetics, although there is some call for the real deal still, especially among woodworkers, who like to have a range of abrasives to work with when they are finishing projects.
When emery is sold in strips and on emery boards, it is attached to a smooth backing with an abrasive, and the grain is often left quite fine, so that the abrasive action will be relatively smooth and gentle. The board or strip must be discarded after the powder starts to rub off or wear away. The minerals can also be sold as a loose powder, allowing people to apply it to grinding and polishing tools so that they can finish various craft projects.
Emery is relatively inert, making it safe to work with as a general rule unless something unusual is included in the mineral blend. As one might imagine, the powder can irritate mucus membranes and eyes, and it should be flushed from the eyes, nose, or mouth with water if it lands on any of these areas. If it is ingested, the mouth should be washed and a glass of water should be drunk; in the event that someone inhales emery, medical attention is advised, as it can damage the delicate tissues of the lungs.