History
After the 1797 discovery that diamond was pure carbon, many attempts were made to convert various cheap forms of carbon into diamond. The earliest successes were reported by James Ballantyne Hannay in 1879 and by Ferdinand Frédéric Henri Moissan in 1893. Their method involved heating charcoal at up to 3500 °C with iron inside a carbon crucible in a furnace. Whereas Hannay used a flame-heated tube, Moissan applied his newly developed electric arc furnace, in which an electric arc was struck between carbon rods inside blocks of lime. The molten iron was then rapidly cooled by immersion in water. The contraction generated by the cooling supposedly produced the high pressure required to transform graphite into diamond. Moissan published his work in a series of articles in the 1890s.
Many other scientists tried to replicate his experiments. Sir William Crookes claimed success in 1909. Otto Ruff claimed in 1917 to have produced diamonds up to 7 mm in diameter, but later retracted his statement. In 1926, Dr. J.Willard Hershey of McPherson College replicated Moissan's and Ruff's experiments, producing a synthetic diamond; that specimen is on display at the McPherson Museum in Kansas. Despite the claims of Moissan, Ruff, and Hershey, other experimenters were unable to reproduce their synthesis.
The most definitive replication attempts were performed by Sir Charles Algernon Parsons. A prominent scientist and engineer known for his invention of the steam turbine, he spent about 40 years (1882–1922) and a considerable part of his fortune trying to reproduce the experiments of Moissan and Hannay, but also adapted processes of his own. Parsons was known for his painstakingly accurate approach and methodical record keeping; all his resulting samples were preserved for further analysis by an independent party. He wrote a number of articles—some of the earliest on HPHT diamond—in which he claimed to have produced small diamonds. However in 1928 he authorized Dr. C.H. Desch to publish an article in which he stated his belief that no synthetic diamonds (including those of Moissan and others) had been produced up to that date. He suggested that most diamonds that had been produced up to that point were likely synthetic spinel.
Read more about this topic: Synthetic Diamond
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