Diamond hardness

July 26, 2005 6:13 AM

If diamonds are the hardest substance known to man, how can you cut them?

How do you cut the diamonds to get them on the cutting wheel? Can you crush a diamond with a hammer? PLease show me some examples of ways to cut a diamond. We are having a huge argument at work and my co-workers think I am nuts because I said there are many ways to cut a diamond or crush one.

posted by askmatrix to Science & Nature (9 answers total)

With lasers. Or with other diamonds. Or so I've been told.
posted by leapingsheep at 6:17 AM on July 26, 2005

wikipedia

You don't really cut a diamond, so much as break it.
posted by cardboard at 6:20 AM on July 26, 2005

Cuts are made by chipping or cutting off pieces along precise angles to gain maximum clarity, based on the crystalline structure of diamond. This page gives a general overview of how the cutting is done, and this page explains what two tools are used.
posted by Rothko at 6:21 AM on July 26, 2005

It's all about the facets. Crystaline structures form facets, whack it along a facet and it breaks.

Or you can use this stuff.
posted by Pollomacho at 6:23 AM on July 26, 2005

Just to clarify, diamond is not the hardest substance known to man, it is simply the hardest natural substance. Fullerite, borazon, Tungsten carbide, and the mythical beta carbon nitride crystal are all supposedly harder than diamond.
posted by Plutor at 6:30 AM on July 26, 2005

Erm, you can cut hard things with things that aren't as hard, it's just the softer thing will wear out more quickly.
posted by cillit bang at 7:29 AM on July 26, 2005

I've heard that you can cut diamonds with other diamonds - or cutting devices that have diamond dust on them.
posted by mulkey at 8:06 AM on July 26, 2005

To clarify even further, hardness and strength are two different qualities (and even then strength is a rather vague term -- engineers have much more precise terms). Diamonds are hard but brittle. The best way to illustrate the difference is this:

If you rub a diamond against the face of a steel hammer, the steel will scratch but the diamond won't. Do the same with a jade stone, and the jade will scratch.

But if you whack the diamond hard with the hammer, the diamond will shatter whereas the jade stone will remain intact.
posted by randomstriker at 9:16 AM on July 26, 2005

Watch "Hey! Spring of trivia!" for proof that if you hit a diamond with a hammer, it will shatter (and end up mere diamond dust).

They crushed a $10,000 diamond for that show.
posted by shepd at 11:22 AM on July 26, 2005