"Rock tumbler grit", also known as "rock polishing grit", is usually a silicon carbide powder that is much harder than the types of rocks that are commonly polished inside of a rock tumbler. Whether it is tumbled in the barrel with rocks and water the abrasion caused with the grit https://silicon-carbide-nozzle04702.blogofchange.com/29447338/detailed-notes-on-4x36-silicon-carbide-sanding-belt