Natural abrasives

Everything in nature can be used for grinding or abrasive materials referred to as natural abrasives. Natural abrasives commonly used are the following:
1. Diamond
(A) for dressing grinding wheel;
(2) grinding and grinding hard materials (such as carbide, cameo glass, stone, etc.).
2. Natural corundum
(1) high-quality corundum (commonly known as the gem) has sapphire (Ti), ruby ??(chromium), etc.;
(2) Normal corundum, black or brown;
Natural corundum, the first one is mainly used for jewelry, two kinds can be used as abrasives, used to make wheel, Whetstone, sandpaper, emery cloth or fine powder, abrasive paste.