Industrial diamond is the trade category covering diamond, both natural and synthetic, used for cutting, grinding, drilling, polishing and other engineering applications rather than as a gemstone. Industrial diamond accounts for the substantial majority of total annual diamond consumption by mass, and the category sits at the foundation of much of modern manufacturing: machine tooling, semiconductor wafer dicing, optical-glass polishing, oil and gas drilling, stone and concrete cutting, and the high-precision work that depends on the hardness and thermal-conductivity properties of diamond.

Production splits between natural diamond unsuitable for gem use, recovered from primary and alluvial mining alongside gem rough, and synthetic diamond produced specifically for industrial applications by the high-pressure high-temperature (HPHT) and chemical vapour deposition (CVD) processes. Synthetic industrial diamond is by far the larger source today; the world's annual industrial-diamond production is dominated by Chinese, Russian, South African and other synthetic output, with annual industrial-grade synthetic production measured in billions of carats.

Forms and grades

Industrial diamond circulates in several physical forms. Bort is the trade term for crushed or fragmented diamond, used principally as an abrasive in grinding wheels, polishing pastes and resin-bond tooling. Single-crystal diamond, both natural near-gem-quality stones unsuitable for facetting and synthetic single-crystal HPHT product, is used for precision tooling, optical components and specialty applications. Polycrystalline diamond compact (PDC) is sintered diamond grit pressed into a tungsten-carbide matrix, used principally in oil and gas drill bits and in metal-cutting inserts. Diamond grit and powder of various particle sizes (from sub-micron to several hundred micron) is used in lapidary and metallographic polishing, in semiconductor wafer dicing, and in jewellery-trade lapping and polishing operations.

The boundary between industrial and gem diamond is not absolute. Some natural rough is borderline between the categories, and a diamond that does not facet well as a gem may be valuable as a single-crystal industrial tool. Conversely, certain CVD synthetic diamond growth has produced material of gem quality alongside industrial production, and the same technology underpins both ends of the synthetic-diamond market.

Historical and trade context

The term "industrial diamond" emerged as a distinct trade category in the early twentieth century, when systematic application of diamond to manufacturing accelerated. The De Beers Industrial Diamond Division (later Element Six) became one of the principal global producers; the GE diamond synthesis programme of 1955 produced the first reproducible synthetic industrial diamond and established the HPHT process that, in modified form, still produces a substantial share of world industrial-diamond output. Chinese synthetic industrial-diamond production rose dramatically through the 1990s and 2000s and now dominates the global industrial-grade market.

For the gemmological trade, the industrial-diamond category is largely a separate world, with its own pricing, technical specifications, and supply chains. The relevant point of contact is in the lapidary trade, where industrial-grade diamond grit is used for polishing wheels, sawing blades and lapping equipment, and in the synthetic-diamond manufacturing infrastructure, where the same plants and processes producing industrial-grade material also produce, at lower volumes, the gem-quality synthetic diamond entering the modern jewellery trade.