GARNET, 80HPA, Barton, Supersack The extremely low chloride levels of Hard Rock Garnet reduces surface contamination versus Alluvial River and Beach Garnets. The sub-angular shape, hardness, and bulk density of Alluvial River Garnet provides fast cutting, ideal for removing thin to medium thickness coatings, mill scale, and rust. Common Usage: Blast rooms, blast yards, bridges, offshore platforms, oil refineries, pipelines, railcar shops, shipyards, storage tanks, and water towers.