What happens if you melt a diamond?

Question

What happens if you melt a diamond?

Answer 1

If you were able to melt a diamond (this would have to be done in a container free of oxygen or the diamond would burn), when it cooled it would not be a diamond anymore. Note that the diamond is made of the element carbon.  To be a diamond the carbon atoms have to be in a special order or stacking relative to each other.  When you melt the diamond the carbon atoms are no longer in this special order and when it cools back down they do not return to the original stacking.

There are other forms of carbon, such as graphite and amorphous carbon.  Most likely you would end up with amorphous carbon. ♦

Answer 2

If you were to heat it in air, it would gradually combust (after all it is carbon)...  I am not sure it would melt per se, but more likely sublime if you were to heat it in a non-oxidizing atmosphere or vacuum...

Answer 3

It goes into liquid form than when cooled hardens.

Answer 4

Diamonds sublime, not melt.   If heated hot enough, it disappears and forms CO2

  If heated in a vacuum without pressure (force mechanically applied), it slowly transforms to graphite.