Diamond is a mineral, one of two crystalline forms of the
element Carbon. It is the hardest substance known,
and interior stones are used as abrasives, in certain
types of cutting tools, and as phonograph needles.
Gem diamonds were first round in streambeds in India
and Borneo; most now come from volcanic pipes in South
Famous diamonds include the Kohinoor, now
among the English crown jewels; the Cullinan, from
which 105 stones were cut; and the blue Hope diamond.
Synthetic diamonds, produced since 1955, are now widely
used in industry, these are created through the utilization
of explosive energy to compress carbon.