Radium-Diamonds

"It is a dangerous practice to get into, criminals being what they are. But it is so interesting. . . ." Dr. C. Everett Field, Director of the Radium Institute of New York was receiving newsgatherers at his laboratory. "Here," he said "look at this blue dish. This was a yellowish glass. We used it in our radium work. Gradually the color changed from yellow to this beautiful blue." He showed them other glass that had been rid of ugly colors and rendered clear blue-white. He showed them diamonds turned in a few days from low-priced jaundiced stones to gems of apparently the first water. How long these stones would stay purified, Dr. Field could not say. But they had not reverted in four years time; perhaps they would never revert. Big Manhattan jewelry houses took notice.

Dr. Field's medical confreres were vexed at his publicity. The explanation: radium activates chemical processes that would otherwise occur very slowly if at all. Chemicals coloring the hard carbon-crystals of diamond are oxidized by radium in salts or even weak solutions. Cost ratio: a $100 yellow stone ( 1/2 karat) was changed to a $700 blue-white stone in four days, using $8,000 worth (100 milligrams) of radium. The less radium, the longer the time necessary. A difficulty: for speediest effects, the gems, and hands of the experimenters, must be directly exposed to the radium, risking burns.

First to demonstrate radium's effect on diamonds was Sir William Crookes of England, who kept a large brilliant in powdered radium bromide for 16 months, when he found it turned pale green and possessed radioactive properties. There was no reversion or diminution of the change in twelve years thereafter. U. S. chemists have since corrobated the green effect in radiumized diamonds. Dr. Field is first to announce a blue-white effect. Other experiments with radium have turned pink synthetic sapphires red or orange; a white sapphire yellow; blue sapphires gray or brownish green; a colorless topaz to amber's color.