What will happend if diamond burned at 1200 degree centigrade?

Answer 1

Probably nothing, but this is an expensive experiment to conduct.

Diamond has the highest melting point of any mineral (3820 degrees Kelvin), which converts to 3,546.85 degrees Celsius.

(The Centigrade measurement has essentially be abandoned. According to Sizes.com: "The problem was that the ice point, the 'temperature of melting ice...at standard atmospheric pressure', which was used to define zero degrees on the centigrade scale, cannot be measured with enough precision.")

Answer 2

If diamond is burned at 1200 degrees Celsius, it will undergo combustion and convert to carbon dioxide gas, leaving behind ash or carbon residue. Since diamond is made entirely of carbon, it will essentially be transforming back into its base element through the process of burning.