About diamond structure

Structure of diamond: In diamond each carbon atom is tetrahedrally attached to four carbon atoms through four strong covalent bonds (Fig. 4.2).Thus no free electrons on carbon are left and all bonding electrons of the carbon atom are engaged. 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 extra ordinary sensitivity to heat rays.
(vi)    It is not affected by harmful radiations.