270 Discovery of Diamonds in the Uralian Mouniaim. 



known ; and the experiments of Dupretz, have shewn the con- 

 version of carbonic acid into carbonic oxide, by means of iron, 

 zinc, and tin ; why then should we consider as impossible, a de- 

 composition of it by means of more easily oxidizable metals, as 

 the bases of lime, alumina, and silica, and their oxides, which 

 occur in the dolomite here described ? Is it not probable du- 

 ring the formation of this rock by the decomposition of carbonic 

 acid, and the high temperature induced by the oxidation of the 

 metals already mentioned, a part of the separated carbon may 

 have been converted into carbonic vapour, which vapour may 

 have been afterwards condensed and crystallized in form of dia- 

 monds, in vesicular cavities in the glowing mass ? 



No diamonds have hitherto been met with in the solid rocks, 

 but only in the alluvium formed by their decomposition, and this 

 because it was conceived that the rocks did not contain them. 

 The rock fragments and minerals of the diamond sand of Brazil 

 differ but httle from those of Poludenka and Adolphskoi valleys 

 in the Urals. Diamonds are found in India as w^ell as in Brazil, 

 always single, and never in nests or veins. Gold and platina ac- 

 company them in the Brazils and in the Urals. In India, gold 

 only occurs ; is it probable that the platina has been overlooked ? 

 In o-eneral they are found in the alluvium, and never in the 

 true mother stone or matrix *. That the black dolomite of the 

 Urals, with its accompanying rocks, may form, by weathering, a 

 similar alluvium, is satisfactorily shewn by geognostical and che- 

 mical investigation. It is thereforo very probable, that this do- 

 lomite, with its transition into talc-slate, is the hitherto unknown 

 matrix of the diamond ; that the diamonds found in the allu- 

 vium formed by its disintegration, had their place in the solid 

 rock, and that the government of Russia, if they considered it 

 for their advantage, and would permit searches to be made in 

 this rock for diamonds, might find that the inquiry would not 

 be in vain. 



• It has been said that the diamond has been found in India, in the sand- 

 stones of the coal formation and new red sandstone. These accounts re- 

 quire confirmation. 



