Ice - Hardest thing known to man?

[Conceptual]

Diamond in a hexagonal packing is no longer diamond so one would be comparing apples and oranges.

[Locrian]

Well I know cubic boron nitride and none of the carbides are harder than diamond at room temperature (most aren't even close on a linear scale), and I'm pretty sure none are harder below room temperature - however I admit I mostly deal with all of these materials at STP. If you could provide additional information I'd appreciate it.

 

I know recently there was an announcement that someone had produced carbon nanotubes that were harder than diamond, but I really dislike their characterization. Frankly hardness just isn't the same at a nano level as it is at a macro level. It is also worth noting that some people have been growing CVD single crystal diamond that is harder than any measured natural diamond, so assuming that natural diamond is as hard as it gets wouldn't be fair.

[YT2095]

When water freezes to form ice, it expands.

 

when water freezes it WANTS TO expand, but if denied this, then you may get something similar to Alotropes of ice, like Ice(1), Ice(2), Ice(3) etc...

 

it`ll still not be harder than Diamond though

[LazerFazer]

People, just look at the industrial process for cutting diamonds. The only way they do that is by using another diamond that has naturally formed to be sharp, so that it can actually cut the diamond that needs to be 'perfected'. If there was another method, they'd probably use that and save the 'cutting diamond' for sale, and therefore increase profit.

 

And yes ,there is now a substance harder than diamond. According to this, its composed of carbon nanotubes.

 

Cheers,

LF