Diamond is the purest crystalline allotrope of carbon having a number of carbons, linked together tetrahedrally.Each carbon atom in a diamond is surrounded by four other carbon atoms and connected to them by strong covalent bonds - the strongest type of chemical bond. The colorless diamonds are used in making gems and colored diamonds like black diamonds are used in glass cutting and in making rock drilling machines.Carbon having Atomic Number 6 & Mass Number 12 occurs in nature abundantly in both free and compound forms.The other Allotropes of Carbon are Graphite, fullerenes, Lonsdaleite, Graphene, and Linear acetylenic carbon (Carbyne).The allotropes of carbon like a diamond, graphite coal, etc are crystalline solid but wood and stone are non-crystalline solid.Additional Information In a diamond, the carbon atoms are arranged tetrahedrally.98Each carbon atom is attached to four other carbon atoms 1.544 x 10-10 meters away with a C-C-C bond angle of 109.5 degrees.The structure is given as follows:It is a strong, rigid three-dimensional structure that results in an infinite network of atoms.This accounts for the diamond's hardness, extraordinary strength, and durability and gives the diamond a higher density than graphite (3.514 grams per cubic centimeter). Because of its tetrahedral structure, diamond also shows great resistance to compression.