PROPERTIES AND TESTS FOR DIAMONDS
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quite black. It is claimed that this method will make it impossible to
substitute stones of lesser value for real diamonds. All the possessor
of the diamond needs to do is to get an ultraviolet ray picture made of
them before temporarily giving up the stones and then have a second
picture made when they are returned. This method will make it possible
to decide the exact quality of any diamond with almost mathematical
accuracy.
There are two kinds of imperfections or flaws: those which are inherent and others arising from imperfect cutting.
Of
the former, black, or carbon spots are the most discernible. They
range from specks so small that it is difficult sometimes to discover
them with a magnifying glass, to spots and broken, ragged clusters,
quite plain to the naked eye. They are formed often of uncrystallized
carbon or portions of the original element which did not crystallize
with the rest but took one of the other forms of carbon, that is,
graphite or carbonado, probably the latter, and were included in that
which did crystallize. Others are inclusions of foreign matter, iron,
etc. They are considered bad imperfections because they are so easily
detected by the naked eye. It is worthy of observation, however, that
the blackest and most abrupt carbon spots are usually found in the
whitest and finest diamonds. They remind one of human nature, in which
the flaws of great talent are more than ordinarily bad. Not only do
black spots look blacker when set in material of peerless color and
splendor, but they are blacker. Where carbon appears in the lower grade
dia-
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