194 



THE GENESIS OF THE DIAMOND. 



two blocks of steel until the blocks touched without injury to the 

 stone in the slightest clegTee. The pressure is said to have been 



Fig. 1.— Diamond mines in the Kimberley District, South Africa. 



iTO tons to the square inch. It is a very strong reflector of light and 

 refracts incident rays more than any other substance except crocoite." 



« Tal)le of indices of refraction in Dnfrenov's Traite cle Mineralogie. 



