'How to transform diamonds that) are of a yellow hue or otherwise off colour into stones of that blue-white' purity which gladdens the hearts connoisseurs is said to have been: discovered in a curious manner American scientists Dr. Everett Field, Director of the Radium Institute of New York,. tells about it, An ordinary yellow wish glass dish used in laboratory work gradually changed into blue-) white. This led to experiments wita' diamorjis, and about £3,500 worth of radium enhanced the apparent value of a cheap yellow stone something like 700 per cent, in four days by changing its colour. So far og can be judged by tests and observation through four years no stone that has once changed colour regains' its original tint, Two American jewellery houses are making extensive tests of the effects of radium on precious stones.. The: fact is not lost sight of that criminal, may take eq advantage of the ry, but that is no concern of the scientists, However, as diamond cuts diamond, so radium can be used. to thwart criminals, for radium can distinguish paste from genuine gems. Ina dark room a real diamond held near radium emits. phosphorescent glow. A paste stone remains invisible.
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