Description | Translucent brown corundum and emery are the most common forms of corundum, Al2O3 (aluminum oxide). These are fairly common and when ground up, they are the most favorable abrasives. The industrial term “emery,” describing corundum abrasives, is derived from the variety emery, which is mined for abrasive use. Erosion may cause emery to crumble and form sand, called “black sands”. |