Science: Synthetic Diamonds

Most precious stones were synthesized long ago; only the lordly diamond held out. The only synthetic diamonds produced have been microscopic, and there was doubt that they were real diamonds. This week General Electric Co. announced that it has made genuine diamonds big enough to identify with certainty.

G.E.’s diamond-makers—Drs. Francis P. Bundy, H. Tracy Hall, Herbert M. Strong and Robert Wentorf—do not tell in detail how they do it. In general they follow nature’s method, which uses the enormous pressure and heat deep under the earth’s surface. G.E.’s diamond crystals are formed by a giant press that concentrates 1,000 tons on a small metal cup heated to above 5,000° F. In it are carbon (probably graphite) and other secret material. When the matrix cools, it contains diamonds (crystallized carbon) the size of sand but big enough for industrial grinding purposes.