The Probert Encyclopaedia of Rocks & Minerals

EMERY

Emery is an impure fine-grained form of corundum (aluminium oxide) in conjunction with iron oxides and spinel, with the formulae Al2O3 employed widely as an abrasive. Typically emery consists of 60 percent corundum and 40 percent iron oxide in the form of magnetite.
Research Emery