When many people think of diamonds, they think of sparkly gemstones used for engagement rings, but the truth is, only about 30% of diamonds are of “gem quality” and suitable for jewelry. The remaining 70% of mined diamonds, known as bort, are sold for industrial applications.
Diamond is the hardest substance on earth and has the highest thermal conductivity of any material at room temperature, qualities needed for numerous industrial purposes. Diamond is used as an abrasive in grinding, drilling, cutting, and polishing, and has proven to be more cost-effective compared to other abrasives in many industrial processes because it cuts faster and lasts longer.
Diamond also has chemical, electrical, optical, and thermal properties that make it ideal for wear- and corrosion-resistant coatings, special lenses for laser radiation equipment, heat sinks in electrical circuits, wire drawing, polishing silicon wafers and computer disk drives, and other applications.
Are synthetic industrial diamonds as good as natural ones?
While the majority of mined diamond is industrial grade, it represents a mere 3% of the diamond used in industry. The remaining 97% are synthetic diamond, a material chemically identical to natural diamond but which can be manufactured in large quantities and tailored to specific applications. Some more interesting facts about synthetic diamond, according to the U.S. Geological Survey, are:
In 2013, total domestic production of industrial diamond was estimated to be 104 million carats, and the United States was one of the world’s leading markets.
Total domestic secondary production of industrial diamond was estimated to be 37.3 million carats.
The major consumers of industrial diamond are computer chip production, construction, machinery manufacturing, mining services (drilling for mineral, natural gas, and oil exploration), stone cutting and polishing, and transportation systems (infrastructure and vehicles).
The differences between synthetic and natural industrial diamonds
Synthetic diamonds are formed by high-pressure, high-temperature (HPHT) technology or by Chemical Vapor Deposition (CVD). Both technologies were developed in the 1950s. The HPHT method works by exposing carbon and graphite to high pressure and temperature, similar to the natural geologic factors that form diamonds (at depth of more than 100 km within the Earth), while CVD accomplishes the same result in the opposite environment, low temperature and pressure.
According to the Gemological Institute of America (GIA), most synthetic diamond producers are shifting to the CVD process because of its lower cost. This method also creates colorless diamonds closer in appearance and quality to natural stones, some of which are making their way into the gemstone market. GIA researchers have conducted tests on CVD-produced diamonds to discover signatures that can be used to tell the difference between CVD and natural diamonds. A previous article addressed how without FT-IR Spectroscopy, you may not be able to tell the difference between synthetic or natural diamonds.
While the synthetics may be improving in quality, when it comes to jewelry they are still no match for natural, gemstone quality diamonds. Natural diamonds, both gem and industrial quality, are the product of either open pit or underground mining, in which diamonds are contained in kimberlite pipes, or they are extracted from alluvial deposits in riverbeds, coastal, and undersea locations. Each scenario requires an efficient and streamlined mining process to recover the most diamonds in the most economical way.
Energy Dispersive X-Ray Fluorescence (EDXRF) is a nondestructive tool for determining the authenticity of colored gemstones and their geographical origin. Depending on the geological setting, precious gemstones like rubies, emeralds or sapphires from different origins often exhibit a characteristic combination of trace elements at different concentrations. Identification and quantification of such elements may allow tracking an emerald, for example, down to its location of origin such as Colombia, Brazil, Afghanistan, Zambia or Zimbabwe. Similarly the presence of certain trace elements also helps to distinguish between a valuable naturally formed gemstone (e.g. ruby) and a worthless synthetic crystal (e.g. synthetic ruby).