Diamonds are forever, right? Really?
March 22, 2010 8:12 AM   Subscribe

A diamond can't be scratched. But can a diamond be crushed?

Diamonds can't be scratched by anything lower than itself on the Mohs scale. (There are some wacky exotic materials harder than diamond, but let's just go with diamond for the moment.)

How does this hardness transfer to compression and torsional strength?

* Can you crush a diamond in a common industrial machine press?

* If you could magically create a human shaped statue out of pure, flawless diamond, and you started whacking it with a baseball bat, would you do anything? Maybe knock a finger off?

* If you could magically create an entire building out of diamond (i.e. a common house structure framed, sided and roofed with diamond), how would it handle the twisting forces of an earthquake, hurricane, tornado, etc? Would it even be able to hold itself up under its own weight?
posted by Cool Papa Bell to Grab Bag (13 answers total) 3 users marked this as a favorite
 
Not a scientific answer at all:
my friend broke the diamond on her engagement ring, all the way to the inscription, as well as two of the platinum prongs holding it. And she doesn't even know how she did it (no, she wasn't drunk!)
posted by Neekee at 8:15 AM on March 22, 2010


Unlike hardness, which only denotes resistance to scratching, diamond's toughness or tenacity is only fair to good.

For lots more reading:
http://en.wikipedia.org/wiki/Material_properties_of_diamond
posted by cschneid at 8:16 AM on March 22, 2010 [1 favorite]


In short, diamonds have cleavage planes. They can be chipped, or "broken" or, well...cleaved if they're struck at the right angle. They can be ground down, using other diamonds.

So, the press? If it strikes at a cleavage plane. Yes, to the statue, though likely with an aluminum bat more than softer wood, and the last? I don't really know.
posted by peagood at 8:18 AM on March 22, 2010


Presses for crushing diamonds have been around for decades, but require a bit more pressure than normal industrial presses (50,000 atmospheres). That's how man-made diamonds are made.
posted by blue_beetle at 8:18 AM on March 22, 2010


A guy my dad knew got the wizard idea that he could find out if his diamond was real by hitting it with a hammer.

It was real. He also crushed it.
posted by dunkadunc at 8:20 AM on March 22, 2010 [23 favorites]


Of course diamonds can be crushed; they're not indestructible. In fact, they can be cut with saws using diamond dust as a sort of grit on the blade.
posted by Halloween Jack at 8:31 AM on March 22, 2010


"Diamonds are forever, right? Really?"

Diamonds burn. In fact, the first proof that diamonds were merely a crystalline form of carbon was burning one. And, better yet, they blend!
posted by paulsc at 8:32 AM on March 22, 2010 [7 favorites]


This question was answered clearly the other day in metatalk... That yes, indeed, they're not all that hard to crush.
posted by TomMelee at 9:04 AM on March 22, 2010


Peagood's got it: Diamonds are fairly easy to break. Top of the hardness scale, but that's not the same as fracturability.
posted by Ys at 9:11 AM on March 22, 2010


Also, see the derail in this recent thread.
posted by Confess, Fletch at 9:38 AM on March 22, 2010


Think about what raw diamonds look like.

Now think about what diamonds in an engagement ring look like.

Diamonds are not indestructible -- we partially destroy them as an element of making them into the thing we value.
posted by jacquilynne at 10:22 AM on March 22, 2010


To unpack jacquilynne a bit -- to get the diamond in your ring, a rough diamond has to be cut and polished. So, obviously, diamonds can be cut along their fracture planes, and ground down.
posted by musofire at 10:50 AM on March 22, 2010


Thanks, all. Apparently no significant compression and torsional strength to match hardness.

Diamonds are not indestructible -- we partially destroy them as an element of making them into the thing we value. ... So, obviously, diamonds can be cut along their fracture planes, and ground down.

And they're just as obviously cut and ground with other diamonds.
posted by Cool Papa Bell at 11:51 AM on March 22, 2010


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