Emery (or corundite) is a dark granular rock used to make abrasive powder. Emery is named after Cape Emeri, Island of Naxos, where it was first discovered. It largely consists of the mineral corundum (aluminium oxide), mixed with other species such as the iron-bearing spinels, hercynite, and magnetite, and also rutile (titania). Industrial emery may contain a variety of other minerals and synthetic compounds such as magnesia, mullite, and silica.