DIAMONDS ARE TURNED GREEN

Green diamonds, highly prized by gem fanciers, are produced from ordinary white diamonds under bombardment by atomic particles in the cyclotron, atom-smasher, Associate Professor Harry Berman, Curator of the Harvard Mineralogical Museum, reported yesterday following a series of experiments.

Professor Berman is studying crystal coloration and various supposed radio-active effects on minerals. The cyclotron permits quick laboratory duplication of the long-term effects of naturally occurring radioactive substances.

The green color imparted to diamonds by an hour of cyclotron bombardment with deuterons, heavy hydrogen ions, is very much like that characteristic of the occasional diamonds exposed to radium rays, Dr. Berman said.

In either the radium or cyclotron bombardment of the diamonds, Dr. Berman explained, a short lived radioactive form of carbon is produced, together perhaps with some gas, like helium. The theory is that such gas molecules could become tightly lodged in the microscopic crevices of the diamond structure, and could impart the green color through a scattering of light rays.

When the radium-green diamonds, are heated, it is conjectured, the gas molecules bounces from the crevices and the diamond becomes white again. In the cyclotron-green diamonds the heating supposedly simply rearranges the gas particles in such a way as to impart the yellow-brown color. No way has yet been found of dispersing or changing the yellow-brown effect, Dr. Berman said.