"Rock Tumbler grit", also known as "rock polishing grit", is actually a silicon carbide powder that is much harder than the types of rocks that are commonly polished in the rock tumbler. If it is tumbled in a barrel with rocks and water the abrasion caused because of the grit https://johnnywzaaa.gynoblog.com/28510875/the-ultimate-guide-to-silicon-carbide-bipolar-transistor