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THE BOOK OF DIAMONDS
monds
of Africa, it is often not only somewhat scattered, but cloudy and less
distinct. In the pure white brilliant stones of India, it is decidedly
black, and abruptly distinct in formation. Why the carbon inclusions
failed to crystallize with the surrounding diamond, has not been
satisfactorily explained. As they must have been subjected to the same
heat and pressure as the remainder of the crystal, some other agency
whose power was not equally distributed during the process of
crystallization probably failed; again it may be necessary for the
crystallization of carbon that it should be in a certain specific
condition when the heat and pressure assumed to be requisite are
applied. Rapid chemical action whereby carbon in solution is thrown
down in transparent crystals, might surround particles which had
escaped the solvent; on the other hand, the same result might be
attained by the slow accretion of crystallized carbon atoms from a
surrounding composite, to a nucleus of the element.
According
to Dr. C. Everett Field, director of the Radium Institute in New York
City, it is possible to change yellow diamonds, which are comparatively
cheap and plentiful into valuable blue-white diamonds by means of
radium treatment. The process consists in placing enough radium near
the diamond to draw off the impurities in the stone which cause the
yellow color. If more radium is used, the change will occur more
rapidly. The quantity is also governed by the relative hardness of the
jewel. It was found that 100 milligrams of radium, worth about eight
thousand dollars will change one diamond in four days. The experi-
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