DIAMOND: ORIGIN 



irons, for example, in that which fell at Arva in Hungary, and at Canon Diablo in 

 Arizona. 



Many meteoric irons contain small cubes of graphite, having the same crystalline form 

 as cubes of diamond ; this cubic form of graphitic carbon, to which the name cliftonite has 

 been given, is present in the meteoric irons which fell at Arva in Hungary, at Toluca in 

 Mexico, at Youndegin in Western Australia, in Cocke County and at Smith ville in Tennessee, 

 and perhaps also in a few others. It is, however, highly probable that these cubes were 

 originally diamond, and were changed into graphite by the agency of heat, the possibility 

 of such a change being effected artificially by heating diamonds away from contact 

 with air, having been previously mentioned above. If this be so, the occurrence of 

 diamond in meteorites is much more general than has been supposed, and now that 

 attention has been drawn to the matter, it is probable that closer examination will 

 demonstrate the presence of diamond in many other meteorites in which its absence has 

 not been definitely proved. 



C. ORIGIN AND ARTIFICIAL PRODUCTION OF THE DIAMOND, 



The problem as to the origip of the diamond in nature is one which has received no 

 small amount of attention. Many and various are the suggestions which have been from 

 time to time put forward, but few are based on scientific considerations, the majority being 

 purely imaginative, and therefore valueless as working hypotheses. 



Before formulathig any useful hypothesis as to the mode of origin of the diamond in 

 nature, it is necessary to learn as much as possible of the conditions under which diamonds 

 occur in all parts of the globe and in extra-terrestrial matter, and oC the manner in which 

 they may be artificially produced. Of neither of these subjects is our knowledge much in 

 advance of that of former years. The artificial production of diamonds is an art yet iu its 

 infancy, and for the elucidation of the problem as to their natural origin, experim{?nts in the 

 artificial production under conditions corresponding as closely as possible to natural conditions, 

 are required. A close study of the conditions under which diamonds occur in nature is 

 desirable therefore, not only as an aid in making such experiments, but also with a view 

 J-.o the collection of detailed information respecting the minerals associated with the diamond, 

 a knowledge of the mode of origin of which would be a substantial help in the solution of 

 the problem. 



Almost every mode of origin, possible and impossible, for the diamond has, at one time 

 oi" aijother, been brought forward : thus some have conceived the formation of diamond to 

 have been brought about by the vital processes of plants ; others have derived the pi'ecious 

 stone i.'om organic remains : and yet others from inorganic substances. Some assume a high 

 temperature to have been an essential of the process ; while others, on the ground that 

 diamond subjected to high temperatures is converted into graphite, consider such a condition 

 an impossibility. A few of the many theories which have been brought forward are set 

 forth below : 



The earliest is that of the celebrated physicist. Sir David Brewster, who unreservedly 

 expressed the opinion that the formation of diamonds was due to the vital processes of 

 plants, the process of formation having been similar to that of the formation of resin, and 

 that the diamond at one time was viscous like a resin. The view that the diamond had been 

 separated out from the sap of some plant in much the same way as a form of silica, the 

 so-called tabasheer, is separated out and deposited in the knotty stems of the bamboo, 



