found in large deposits in Sri Lanka, Malagasy Republic, the former USSR,
South Korea, Mexico, and Czechoslovakia. Economic deposits at Val Chisone
(Italy). Small hexagonal crystals in marble at Ogdensburg, New Jersey (USA)
and in gneiss at Edison, New Jersey (USA).
Natural: It is formed in high-grade metamorphic rocks as a final
product of the carbonization of organic materials. It is probably also
a primary magmatic substance in some pegmatites and hydrothermal veins.
Synthetic: Coke is a graphite product that is about 94% carbon.
It is produced by heating soft coal in an oven that has no access to air.
Most of the impurities sublime off, leaving fairly pure carbon. Lampblack
is produced by the burning of methane gas in a special compartment that
has no access to oxygen and has water-cooled walls. As the oxygen-starved
yellow flame burns, it produces a dense black soot that collects on the
cooled wall. Most synthetic graphite is obtained from petroleum coke, the
black tar that remains after all of the useful fuels and organic lubricants
have been distilled from crude oil. This tar is treated in an oxygen-free
oven to burn off any remaining organic impurities. The material that remains
is a high percentage of graphite.
crystals of Diamond
occur in the kimberlites of South Africa, Yakutia (former USSR), Murfreesboro,
Arkansas (USA), Brazil, Zaire, Sierra Leone and Ghana. Small, nongem-quality
crystals are found in Brazil, Venezuela, Zaire and other countries.
Natural: It is formed in ultramafic rocks, especially kimberlite
breccias, and in detrital sedimentary deposits derived from them, in river
and marine placers. A rare form of hexagonal "diamond" known as Lonsdaleite
is found in certain meteorites, such as those from Canyon Diablo, (USA).
This octahedral diamond crystal, found in South Africa, is embedded
Synthetic: Most industrial-grade diamonds are produced, with
the aid of catalysts, by subjecting high-grade graphite to extremely high
temperature and mechanical pressure over a period of several days or weeks.
Dr. Guy Suits of the General Electric Company synthesized the first man-made
diamonds in 1957.
Natural: Minute quantities of the Buckminsterfullerenes, in the
form of C60, C70, C76,
and C84 molecules are produced in nature, hidden in
soots and formed by lightning discharges in the atmosphere. This family
of carbon molecules was discovered in 1985 and resulted in a Nobel
Prize in chemistry in 1996. Recently, Buckminsterfullerenes were found
in a family of minerals known as Shungites in Kaleria, Russia.
Synthetic: Gram quantities of these illusive molecules are available