Emery (rock)

It largely consists of corundum (aluminium oxide), mixed with other minerals such as the iron-bearing spinels, hercynite, and magnetite, and also rutile (titania).

Emery is black or dark grey in colour, less dense than translucent-brown corundum with a specific gravity of between 3.5 and 3.8.

A small quantity of emery is used in coated abrasive products, but its main use in the United States is wear-resistant floors and pavements.

It has been mined on the eastern side of Naxos for well over two thousand years as mentioned by Pliny the Elder's The Natural History, book XXXVII, chp.

However, demand for emery has decreased with the development of sintered carbide and oxide materials as abrasives.