Diamond them with diamonds. Much more recently (tens to hundreds of million years ago), they were carried to the surface in volcanic eruptions and deposited in igneous rocks known as kimberlites and lamproites. Synthetic diamonds can be grown from high-purity carbon under high pressures and temperatures or from hydrocarbon gas by chemical vapor deposition (CVD). Imitation diamonds can also be made out of materials such as cubic zirconia and silicon carbide. Natural, synthetic and imitation diamonds are most commonly distinguished using optical techniques or thermal conductivity measurements. Diamond is a solid form of pure carbon with its atoms arranged in a
Diamond Alkali Diamond Alkali Diamond Alkali Company was an American chemical company incorporated in 1910 in West Virginia by a group of glass industry businessmen from Pittsburgh. The company soon established a large chemical plant at Fairport Harbor, Ohio, which would operate for over sixty years. In 1947, the headquarters of the company was moved from Pittsburgh to Cleveland. In 1967, Diamond Alkali and Shamrock Oil and Gas merged to form the Diamond Shamrock Corporation. Diamond Shamrock would go on to merge with Ultramar Corporation, and the combined company, Ultramar Diamond Shamrock Corporation, would in turn be acquired by Valero Energy Corporation