You can only cut a diamond with a diamond...

[kermit911]

Please explain...  You can't cut a diamond with a good drill bit, or a nice sledge hammer?  What make a diamond so tough?

Thanx

[Clanad]

The carbon structure od diamonds at the atomic level is quite unusual.  The carbon atoms actually share electrons with adjacent carbon atoms forming a 3-D structure. The diamonds arose, the earliest nearly 2.5 billion years ago, along volcanic pipes from deep within the earth, which was responsible, in part, for the carbon structure and hardness. The structure is such that the speed of light is decreased to about 80,000 miles per second when passing through diamonds...

[Gef]

Diamond is the hardest naturally occuring substance due to every carbon atom forming four very strong bonds with other carbon atoms in a giant covalent network. By hardness we mean resistance to wearing away. If you hit a diamond with a sledge hammer it would shatter like a piece of glass. Also, if you dropped one in a fire it would burn.

[brachiopod]

I am afraid you have to heat a diamond up to about 800oC and then drop it into liquid oxygen if you are going to get it to 'burn'.