Synthetic diamond is diamond produced in a technological process. Claims of diamond synthesis were documented between 1879 and 1928 but none have been confirmed. In the 1940s, research began in the United States, Sweden and the Soviet Union to grow diamond using chemical vapor deposition (CVD) and high-pressure high-temperature (HPHT) processes. The first reproducible synthesis was in 1953. CVD and HPHT still dominate the production of synthetic diamonds, whose properties vary depending on the process used. The hardness, thermal conductivity and electron mobility of some manufactured diamonds are superior to those of natural diamonds. Synthetic diamond is used in cutting and polishing tools, abrasives and heat sinks. Electronic applications of synthetic diamond are being developed, including high-power switches at power stations, high-frequency field-effect transistors and light-emitting diodes. Both CVD and HPHT diamonds can be cut into gems and produced in various colors (pictured). (Full article...)