Industrial minerals, namely, alumina, amorphous silica, attapulgite, barium sulphate, barytes, bentontite, borates, calcium silicate, calcium carbonate, calcium sulphate, calcium oxide, carbon black, ceramic powders, chromium corundum, cordierite, diatomite, diatomacious earth, magnesium oxide, montmorillonite, perlite, ferriferous sandstone, ferrosilicon, magnesium silicate, crystalline silica (sand), sialon, silicon carbide, sillimanite, smectite clay, strontium carbonate, talc, vermiculite...