Do Diamonds burn or melt?

In some studies researchers said that the Diamonds can melt or broken into pieces on burning or melting it in the absence of oxygen at a temperature of 4027 degree Celsius or 7280 degree Fahrenheit. Before being transformed into fluid the Diamond broken into Pieces of Graphite which is a compound of Carbon. An another mystery about the Diamond is Can they be destroyed with the help of acids The answer is simply No, They can not be dissolve with the help of Acids due to togetherness of carbon and hydrogen ions.

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