Why does a Diamond have a high melting point?

Answer. 

Diamond is a precious stone found in nature. However, it is the strongest element in nature too. Diamond is a fine example of carbon’s polymorphism and in this term, the main reason behind diamond’s high melting point lies.

Suppose we carefully observe a diamond’s chemical formation. In that case, we will find that diamonds are made up of carbon atoms in a manner where each and every carbon atom is covalently bound with 4 other carbon atoms and form a distinctive molecular shape. This molecular shape gives it immense strength and millions and billions of covalent bonds allow the diamond molecules to have stability (i.e. low energy state).

Therefore diamond molecules require a huge amount of energy to reach their melting point and thus the melting point is this high.