76 POPULAR SCIENCE MONTHLY. 



shapes would be roughly simulated by the Pyramids of Egypt if 

 they could be seen, combined with their reflected images, in a placid 

 lake, or, better to meet the conditions of the country, in a desert 

 mirage. It is a peculiar property of diamond crystals to have con- 

 vexly rounded faces, so that the edges which separate the faces are 

 not straight, but gently curving. Less frequently in the African 

 mines, but commonly in some other regions, diamonds are bounded 

 by four, twelve, twenty-four, or even forty-eight faces. These 

 must not, of course, be confused with the faces of cut stones, which 

 are the product of the lapidary's art. 



Geological conditions remarkably like those observed at the 

 Kimberley mines have recently been discovered in Kentucky, with 

 the difference that here the shales contain a much smaller percent- 

 age of carbon, which may be the reason that diamonds have not re- 

 warded the diligent search that has been made for them. 



Though now found in the greatest abundance in South Africa 

 and in Brazil, diamonds were formerly obtained from India, Bor- 



Copyright, l^y.t, by iieorge F. Kunz. 



Four Views of the Oregon Diamond ; enlarfred about three diameters. 

 (Owned by Tiflany and Company. ) 



neo, and from the Ural Mountains of Russia. The great stones of 

 history have, with hardly an exception, come from India, though 

 in recent years a number of diamond monsters have been found in 

 South Africa. One of these, the " Excelsior," weighed nine hun- 

 dred and seventy carats, which is in excess even of the supposed 

 weight of the " Great Mogul." 



Occasionally diamonds have come to light in other regions than 

 those specified. The Piedmont plateau, at the southeastern base 

 of the Appalachians, has produced, in the region between southern 

 Virginia and Georgia, some ten or twelve diamonds, which have 

 varied in weight from those of two or three carats to the " Dewey " 

 diamond, which when found weighed over twenty-three carats. 



It is, however, in the territory about the Great Lakes that the 

 greatest interest now centers, for in this region a very interesting 

 problem of origin is being worked out. No less than seven dia- 

 monds, ranging in size from less than four to more than twenty- 

 one carats, not to mention a number of smaller stones, have been 



