Gemological laboraties

I was watching Modern Marvels on the History Channel, and they used "this scientific machine . . ." to cut diamonds.  It used diamond powder to cut them, because the surface needs to be as hard as the diamond itself.  But then how do they get the powder?

>>1
First off, diamonds are pretty much unbreakable for all practical purposes, so it takes a high energy collision between two or more diamonds to produce any fracturing.  Then, diamond fractures are usually smooth and large, so many high energy collisions are necessary, as in meteor impacts.  This is where most diamond powder is collected, sifted from sand with magnets, and shipped to gemological laboratories.

Fun fact: most diamonds don't actually have a hexagonal atomic structure.  It's usually irregularly-pentagonal, with the most stable forms hexagonal.  This is why when diamonds do break, it is so cleanly.