The various such forms of the element are called allotropes of that element. Allotropes always exhibit different physical properties but possess same chemical properties The allotropes of carbon are of two types — the crystalline and amorphous carbon. Diamond and graphite are crystalline carbon. Charcoal coke, lamp black soot, etc are amorphous or non-crystalline carbon Allotropes of an element consists of only one kind of atoms with their different arrangement having different physical properties but same chemical properties. Pure carbon occurs in the natural form of two allotropes,namely diamond and graphite. Diamond and graphite are chemically identical, both consisting of carbon atoms only. Diamond and graphite differ only in the arrangement of carbon atoms in their crystals. This leads to the difference in their appearance and many other physical properties.