THE BOOK OF DIAMONDS
carbon
was separated by electricity from carbonic acid surrounded by reducing
agents. Other chemists have thought that diamonds may have been formed
by the gradual decomposition of gaseous hydrocarbons, whereby the
hydrogen, escaping through fissures, was converted into water by
oxidation, part of the carbon was converted into carbonic acid and the
remaining carbon was left crystallized in a free state. It is said
black diamond was obtained by Rousseau by subjecting acetylene to
electric furnace heat.
It
is reported that Dr. Burton of Cambridge has succeeded in
crystallizing carbon by means which do not include very high
temperature and great pressure. His method is founded on the idea that
diamonds are simply a denser form of charcoal. He used an alloy of lead
and metallic calcium to hold charcoal in solution. To separate the
calcium he introduced steam into the fused mass, whereby part of the
carbon crystallized. It is said that if the alloy is in a state of
ignition when the steam is introduced, graphite crystals are formed;
but at a lower temperature, diamond crystals. The crystals obtained by
Dr. Burton are said to possess an unusually high power of refraction.
These experiments have strengthened the belief of some that Nature used
some solvent for carbon, as yet unknown, which by evaporation left part
of the carbon in the crystallized form, as the crystals of other
minerals are.
"It
has been said that the sharp edges of the diamond crystals found in the
Kimberlite would be impossible, had they been formed in a molten mass
but as Moissan produced such diamond crystals, though small, from
charcoal
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