De
Boot asserted that Rudolf II could take not only color, but flaws from
diamonds. If the statement was true, the secret died with him. It has
been stated of late that the emanations of radium permanently improve
the color of diamonds, changing the yellow to a bluish tint, but time
for proof is yet wanting, and the cost and scarcity of radium debars
thorough investigation at present. That radium has a great influence on
some diamonds has been demonstrated. Under its influence some stones
will become brilliantly phosphorescent, and the color of the light
varies with different stones. Two large diamonds, one blue, the other
black, as the radium was brought near them, glowed brilliantly,
retaining the light for some little time after they were removed from
the influence of the radium, the black stone holding the light somewhat
longer than the blue. This was reversed when the stones were subjected
to the ultra violet ray, as the black stone showed a red light for 15
seconds and the blue stone shed light for five seconds after the black
stone had lost its brilliancy. Actual contact of the two substances is
not necessary to produce the result, as a mixture of radium and
willemite held ten inches under the board on which the diamonds lay,
caused them to glow in the same manner. Willemite, a zinc silicate, it
was found, in combination greatly increased the power of the radium.
Some
twenty years ago it was discovered that dishonest persons were "
painting " diamonds. This was done by applying a purple dye or ink to
the under side of the stone on and around the culet. When dry this was
rubbed down until the paint became imperceptible to the
casual glance, but leaving enough on withal to neutralize 10
