What's On The Edge Of A Diamond?

I realise it's a crystal lattice, but the diagrams merely show the edges going on forever, how diamonds have fixed shapes, what happens at edges? Surely there aren't just carbon bonds floating around.

4tran, help me out here.  If your option "c" was true, then a microscopic portion of the diamond would transform from the hardest substance to the softest.  Even being so small, that soft substance could be abraded off.  That leaves danglers, which become more graphite, and then the process repeats.  That suggests that diamonds would disintegrate into graphite (or graphite flaws destroy the diamond).  That doesn't seem to happen with diamonds that are worked (as industrial diamonds in drill bits, etc.) such that they would reveal such a process.

>>13
First, I admit I'm not sure exactly how diamonds change to graphite over time, but it does happen, and takes millions of years (can't find data at the moment).

Given anything, if you abrade it long enough, it will _eventually_ disintegrate.  Every time you use that diamond drill, some carbon atoms are falling off.  I claim that this process is far faster than the transition to graphite (continuous abrasion will destroy a diamond long before a million years).  As a result, most of the carbons close to the surface will get rubbed off long before they get a chance to turn to graphite.