You have to use another with a hardness of over seven about the Mohs scale; if not, you will just be wasting electricity by working your tumbler. For advanced Digital applications, huge one crystals of SiC could be developed from vapour; the boule can then be sliced into wafers very https://www.quora.com/profile/Trevor-Flatcher-2/Role-of-Silicon-Carbide-in-Fuel-Cells-Silicon-carbide-SiC-plays-a-crucial-role-in-advancing-fuel-cell-technology-off