MAN-MADE DIAMONDS SUITS 445 



With this filial step, America acquired for the first time an independ- 

 ent source of industrial diamond, a material which is very important 

 to the industrial economy, and which is absolutely vital in key defense 

 industries. The assurance of a steady supply of industrial diamond 

 has encouraged broader use of this exceptional material for new appli- 

 cations. And, surprisingly enough, the new Man-Made product has 

 turned out to be better than natural diamond for many applications. 



Man-Made diamonds are grown under controlled conditions, and re- 

 markable control can be exercised over the properties of the tiny 

 crystals. For some purposes it is desirable to produce friable crystals, 

 so that fresh cutting surfaces will be exposed during use ; such crystals 

 can be grown. For other purposes — for example, metal-bonded circu- 

 lar saws — the ideal crystal would be an octahedron of the correct size; 

 such crystals can be grown. This is an improvement on natural dia- 

 mond because tiny crystals are not recovered from natural sources, and 

 hence fine mesh-size, natural diamond is generally produced by crush- 

 ing, which does not readily yield the desired crystal shape. Thus, 

 nature's hardest substance is now subject to quality control, which has 

 significantly enhanced its industrial usefulness. 



A "diamond mine," in Detroit, part of the General Electric Co.'s 

 Metallurgical Products Department, is now one of the largest single 

 sources of industrial diamond in the world. The product is made 

 reliably and at a price that is directly competitive with natural dia- 

 monds. The total production of diamonds from this mine to date is 

 not properly measured in carats, but in tons. 



Most industrial diamonds, including Man-Made diamonds now on 

 the market, are very small : up to about half a millimeter in diameter 

 and weighing only about a thousandth of a carat or less. However, 

 diamonds in these small sizes in the form of abrasive grit fill a large 

 portion of industrial needs. Meanwhile, considerably larger Man- 

 Made diamonds — 1 or 2 mm. long and of good quality — can be made. 



Research continues toward the development of larger industrial 

 stones, up to and including the carat-size diamonds required for oil- 

 drill bits and wiredrawing dies. By growing the crystals in a multi- 

 step process — adding a layer at a time — it has been possible in the 

 laboratory to make diamonds weighing more than two carats (pi. 3). 

 It must be noted, however, that these crystals are quite imperfect. 

 They are not very strong because of inclusions, particularly between 

 the layers, and because of internal strains in the crystal structure. 

 They are definitely not the kind of clear, perfect stones suitable for 

 polishing into something of interest to the ladies. 



The scientific achievement of Man-Made diamond, and the commer- 

 cial success of the product, have served to stimulate broad interest in 

 high-pressure research at laboratories all over the world. Approxi- 

 mately 200 laboratories are now equipped for superpressure research, 



