This strong covalent bonding in its structure makes it hardest natural substance and a non-conductor of electricity.
Properties and Uses:
(i) Diamond is a hard substance and because of this hardness, it is used for making glass cutters and rock borers for drilling.
(ii) It has a high refractive index and is therefore used as a precious gem for making jewellery etc.
(iii) It is non-conductor of heat and electricity.
(iv) It is chemically unreactive.
(v) It is used for precision thermometers because of its extraordinary sensitivity to heat rays.
(vi) It is not affected by harmful radiations.