Diamond has a giant structure of carbon atoms held together by strong covalent bonds: - Diamond is made up of many strong covalent bonds, so a lot of energy is needed to overcome them, so diamond has a high melting and boiling point- Diamond is insoluble because much energy is needed to break the strong covalent bonds- Diamond is very hard because much energy is needed to break the strong covalent bonds between the surface atoms – it is useful for cutting tools and drill tips- Diamonds does not conduct electricity because there are no charged particles free to move