Eighty percent of the diamonds mined annually are used in industry; 4 times that production is grown synthetically for industry - that's a total of over 500 million carats or 100 metric tons. Diamond is a fundamental industrial material that affects our daily lives. Because diamond is the hardest substance, it is used to cut, grind, and polish most hard substances. It fashions stones, ceramics, metals, and concrete, as well as eyeglasses, gems, and computer chips. Its growing specialty-uses include blades, some used in critical surgery; specialty windows; and heat spreaders. And of course diamond phonograph needles reproduced music for 50 years.

Diamond has three primary roles in industry: it is used as a cutting tool, it is imbedded in another material and used as a tool or abrasive, and it is turned to powder or paste for grinding and polishing. Diamond is selected for such use where its hardness and resistance to abrasion - its long working life and fast cutting action - outweigh its costs. Moreover, diamond's resistance to wear enables it to cut reproducibly time after time, a requirement of automated production. Diamond machining tools for turning, milling, and boring are preferred where finely finished surfaces of high precision are needed. Diamond is used for machining a wide variety of plastics, glasses, and metals, shaping products such as the drums for copying machines, polygon mirrors in laser printers, and aluminum-alloy pistons in automobile engines. However, diamond cannot be used for machining alloys of iron. Under intense machining conditions the diamond abrades very quickly against some materials, apparently because of a high-temperature reaction between iron and carbon.

Photographs courtesy of GE Superabrasives