Diamonds are found in alluvial (loose earthy material deposited by running water) formations and in volcanic pipes, filled for most of their length with blue ground or kimberlite, an igneous rock consisting largely of serpentine. (Davis, 2003) At the surface the blue ground is weathered to clay called yellow ground. Diamantiferous (or diamondiferous), or diamond-yielding, earth is mined both by the open-pit method and by underground mining. After being removed to the surface, it is crushed and then concentrated. Passing the concentrated material in a stream of water over greased tables does sorting. The diamond, being largely water repellent, sticks to the grease, but the other minerals retain a film of water, which prevents them from adhering to the grease. The diamonds are then removed from the grease, cleaned, and graded for sale. A diamond is characterized as a clear hard solid formed by a covalent network of carbon atoms. (Khoury, 1990)
Technology, however, has led to a stark reality: all diamonds regardless of quality can be commercially synthesized, as can sapphires, rubies, and other gems. The technology is relatively new and was not pioneered by a major diamond producer, not even the Soviet Union where 85% of its current industrial diamond need is met by synthetics. (Minerd, 1999)
Artificial diamonds have been researched since the early 1950s. The first success in synthesizing diamonds was recorded in 1953 by the Swedish firm Allmana Avenska, which was able to synthetically produce a 1-millimeter diamond of industrial quality. Moreover, in 1955 the General Electric Corporation also announced success in creating synthetic diamonds. The major breakthrough in synthesizing gem quality diamond was realized by the Russians in 1967. (Khoury, 1990) General Electric was to succeed in 1970 in producing gem quality diamonds. Today most industrial diamonds are produced artificially. In 1986 researchers at Pennsylvania State University developed a low pressure, low-temperature process for making super hard diamond films. They form them by reacting methane and hydrogen gases in a microwave oven at atmospheric pressure (Business Week, 1986). This discovery should further increase the supply and reduce the price of industrial diamonds. Continuing developments of high-pressure synthesis techniques have enabled a further extension of the range of polycrystalline diamond (PCD) products, primarily for oil well drilling. Moreover, improved drilling product having a higher abrasion resistance and greater thermal stability than existing products has been developed and introduced to the market. A high-strength braze, designated DBF1, has been developed for use with the more thermally stable cutting element. (Minerd, 1999)
Artificial diamonds are made by subjecting graphite (one of the three crystalline forms of carbon) to very high temperatures and pressures. (Miller, 1999) Most of pure diamond’s fundamental properties are retained in artificial diamonds. For example, artificial diamonds have extreme hardness, broad transparency, high thermal conductivity and high electrical resistivity. Contemporary artificial diamonds passes through a process where carbon are mixed together with other materials that help catalyze the process. Some minerals such as sodium tetrachloride and nickel-cobalt alloys are two that have been used successfully. Consequently, an activation of pressure and the application of heat ranging between 700-850o Celsius should be done for more or less 48 hours. Nevertheless, a more exciting way of doing it is being pioneered in Israel where a `shock wave’ process uses an explosive blast to create the pressure and temperature conditions to transform graphite into diamond. (Minerd, 1999)
Similarly, artificial diamonds may improve everything from computer screens to space flight. Diamonds may make airbags smarter, factories cleaner, computer screens thinner, and aircraft faster within the next decade, according to researchers. (Khoury, 1990) Despite their toughness, diamonds can be coaxed into giving up their electrons quickly. This property could make computer and television screens nearly paper-thin. Likewise, traditional TV and computer screens are bulky because they shoot electrons from an electron gun to light up a phosphorescent screen. Because of its strength, diamond makes a good semiconductor even at extremely high temperatures and pressures. When used instead of silicon in electronic devices, diamond makes for tough, durable equipment
Artificial diamond making is a very expensive process. Therefore most are produced as small crystals that are used to provide hard coatings for industrial equipment such as grinding wheels, machine tools, wire drawing dies, quarrying saws and mining drills. (Minerd, 1999) Not only are artificial diamonds the hardest substance known, it also has the highest thermal conductivity – tremendous heat can pass through it without causing damage. Today’s speedy microprocessors run hot – at upwards of 200o Fahrenheit. In fact, they can’t go much faster without failing. Diamonds can operate electronically at 600o C and up, while silicon turns to mush at 100o C, the boiling point of water Diamond microchips, on the other hand, could handle much higher temperatures, allowing them to run at speeds that would liquefy ordinary silicon. (Davis, 2003) But manufacturers have been loath even to consider using the precious material, because it has never been possible to produce large diamond wafers affordably. Although, a diamond is an inherent insulator – it doesn’t conduct electricity, several companies have been able to inject boron into the lattice, which creates a positive charge. Until now, though, no one had been able to manufacture a negatively charged, or n-type, diamond with sufficient conductivity.
Reference:
Davis, J. (2003). The New Age Diamond. Wired Magazine. Vol. 11 No. 9
Khoury, S. (1990) The Valuation and Investment Merits of Diamonds. Quorum Books. New York.
Miller, N. (1999) The hard and the soft of it. Geographical. Vol. 71 No. 12 Campion Interactive Publishing Ltd
Minerd, J. (1999) Diamonds promise new benefits. The Futurist. Vol. 33 No. 6 World Future Society
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