Emery, a dull, blue-black mineral, allied in composition to the sapphire, but containing a varying quantity of iron oxide; is found in large masses; is exceedingly hard, and largely used in polishing metals, plate-glass, and precious stones.
Definition taken from The Nuttall Encyclopædia, edited by the Reverend James Wood (1907)
Emerson Tennent, Sir James * Emigrants, The