GEMS, NATURAL AND ARTIFICIAL 



nal stress, break on the smallest provocation a phenom- 

 enon also observed sometimes in the case of the natural 

 diamond. The mere liberation from the intense pressure 

 under which the gems are formed appears to be enough 

 to cause them to fly into fragments. The fragments them- 

 selves, however, have all the characteristic stability and 

 hardness of ordinary diamonds. 



The conditions which may thus be established in 

 the laboratory are duplicated to some extent in the 

 commercial manufacture of certain kinds of steel, 

 which are cooled from the molten state under intense 

 hydraulic pressure; and steel so made may actually 

 contain microscopic diamonds, as Professor Rosel, 

 of the University of Bern, has demonstrated. It has 

 even been suggested that the hardness of steel may be 

 due, in part at least, to the presence of diamond par- 

 ticles everywhere in its substance. Ordinarily these 

 diamond crystals, where they exist in steel, are almost 

 infinitesimal in size; but in one case, in a block of 

 steel and slag from a furnace in Luxembourg, a clear 

 crystalline diamond was found measuring about one- 

 fiftieth of an inch across this being the largest arti- 

 ficial diamond yet recorded. 



The theory of diamond-making being so well under- 

 stood, it may hardly be doubted that the manufacture 

 of these gems will some day be placed on a commercial 

 basis the manufacture, that is to say, of veritable dia- 

 monds, indistinguishable by any tests whatsoever from 

 the products of the mines; this being true of the minute 

 diamonds produced in Professor Moissan's furnace 

 and in the steel ingots. It would be futile to predict 



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