This is a pneumatic rock crusher and mortar set for crushing hard rock into fine powder. The rock crusher bit is 7.75″ x 2″ with a .400″ outside diameter and fits most pneumatic air hammers. It is made of hardened steel and can easily pulverize quartz. The 6″ tall by 6″ inside diameter mortar is 1/4″ thick with a 1/4″ welded bottom, painted black on the outside to prevent rust. Expect some surface rust inside, which won’t affect crushing. Ideal for modern day gold prospectors or miners.