A bit made of solid steel with no moving parts which is used for drilling very hard rocks. Hundreds of industrial diamonds are embedded in the bottom and sides of the it. Diamonds abrade the rock and work like a large grindstone.
There are three type of diamond bits: (a) with natural diamond, (b) with polycrystalline diamond cutters or PDC, (c) thermally stable polycrystalline diamond cutters or TSP. These three types differ in the nature of the cutting elements which crush the rock in a mechanically different way.