THE GENESIS OF THE DIAMOND." 



By Gardner F. Williams, Kimberlcy, South Africa. 



Chemically the diamond is composed of the element carbon in its 

 pure crystallized state. The diamond crystallizes in the isometric 

 system and the most common forms are the octahedron and dode- 

 cahedron, while the (24-sided) tetrahexahedron is not uncommon. 

 Cube diamonds with beveled edges, representing the combination 

 00 00 and qo 2 are occasionally found in the Bultfontein and 

 AVesselton mines at Kiml)erley. South Africa. The diamonds from 

 various mines have distinctive forms of crystallization, or varia- 

 tions of the same forms, so characteristic that those familiar with 

 South African diamond mines and their products can determine 

 positively from which mine any given parcel of diamonds has been 

 obtained. It is not always possible to determine the source of each 

 individual diamond, for similar stones are occasionally found in 

 different mines; but these are exceptions to the rule. There is a dif- 

 ference in the luster, shape, or crystalline form of the diamonds 

 from the various mines that gives each mine some distinctive char- 

 acteristic. In one mine nearly all the crystals are sharp-edged octa- 

 hedrons, while in another dodecahedrons with rounded faces pre- 

 dominate. One might give no end of peculiarities of the diamonds 

 from the various mines, but it will suffice for the purposes of this 

 paper to state the fact that such distinctive characteristics do occur. 



From this observation it may be concluded that the diamonds in 

 the mines of the Kimberley district, which occupies a small area 

 (see fig. 1), did not have a common origin. 



The diamond is the most impenetrable of all known substances 

 and will scratch an}^ other stone or the hardest steel. During his 

 lecture '^ at Kimberle}^, Sir Wm. Crookes squeezed a diamond between 



a Reprinted, with the author's revision and additions, from Transactions 

 American Institute of Mining Engineers, 190.5. Read at Lake Superior meeting, 

 September. 1904. 



6A lecture delivered before the British Association at Kimlierley. September 

 5, 190.5. 



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