Abrasive

Anabrasiveis something that is very hard. It is also rough. It is used to rub things so they get smooth. When abrasives are glued to paper, it makessandpaper.Aluminium oxideis a common abrasive. Abrasives are used to make the ends of wood pieces smooth and to smooth the cut ends of metal. The hardest natural abrasive isdiamond.Diamond is commonly used in saw blades designed to cut tile or stone.