Alt. thread title: how much does the DiS crowd-mind know?

Post things you've wondered about, that you could easily find the answer to by jumping onto google, but for some reason, you've never searched for the answer. Then let's see whether the DiS collective can answer these questions without having to ask google.

I've always wondered, if diamonds are one of the hardest substances on earth, how did people manage to cut them into, well, diamond shape? Like, in the olden-days, before they had lasers 'n' such?