440 ANNUAL REPORT SMITHSONIAN INSTITUTION, 19 64 



The task itself is conceptually simple. Graphite is composed of 

 carbon atoms, tightly bound in planes, with comparatively weak atomic 

 forces holding the planes together ; the flaky character of graphite is 

 the macroscopic evidence of this atomic structure. Diamond is com- 

 posed of precisely the same carbon atoms squeezed together to achieve 

 substantially uniform inter-atom distances throughout the lattice. 

 Thus, the diamond lattice is a neat packing configuration which gives 

 each atom a tight hold on each of the four atoms arrayed around it. 

 In other words, to turn graphite into diamond, all one must do is press 

 it into the more compact atomic arrangement of diamond, as is shown 

 in plate 1, fig. 1. What could be simpler? 



But, alas, as countless investigators over the years have learned to 

 their agonizing dismay. Mother Nature did not intend her own achieve- 

 ment — probably performed at mysterious, unexplored depths far 

 beneath the surface of the earth — to be easily accomplished by man. 

 The late Professor Percy Bridgman of Harvard, a Nobel laureate for 

 his work on high-pressure phenomena, put it succinctly. "Graphite," 

 he said, "is nature's strongest spring." 



Or, in the less grammatical phrase of one of our laboratory associ- 

 ates, it might be said that "it is easy to squeeze carbon atoms together, 

 but very difficult to keep them squz." 



Professor Bridgman spent many years trying to make diamonds 

 during the 1920's, 1930-s, and 1940's, and found serious natural road- 

 blocks at every step on this road. The most serious roadblocks were : 

 (1) An understanding of the diamond-making process, and (2) the 

 requirement of high pressure and high temperature simultaneously, 

 both held for an appreciable mterval of time. Bridgman produced 

 pressures which were much greater than required, but the "spring" 

 relaxed to graphite when the pressure was reduced. On the basis of 

 what he learned, Bridgman concluded that all previous claims to 

 success in diamond-making were based on wishful thinking and not 

 scientific proof. 



In 1951, my associates ^ and I decided to launch a new, all-out assault 

 on this problem. We resolved to delve into the process whereby 

 diamond might be made, using not only new techniques for attaining 

 fantastically high pressures, but also for attaining the simultaneous 

 high temperatures that would be required to "latch" this spring : thus, 

 to form diamond from graphite. 



Let us now discuss three aspects of the diamond problem in turn : 

 the pressure, the temperature, and the chemistry — and then add a 

 comment about a fourth factor — time. 



Using the strongest available materials, unique prestressing tech- 

 niques, and geometrically complex designs which permit the microflow 



s A group led by A. J. Nerad and Including Drs. F. P. Bundy, H. T. Hall, H. M. Strong, 

 K. n. Wentorf, Jr., and H. P. Bovenkerk. 



