318 Dr Petzholclt on the Formation of the Diamond, 



of Russian diamonds, in the course of which he came to the 

 opinion, that the only way of explaining certain structural 

 phenomena, such as cracks and flaws in the interior, and a 

 scaly appearance on the external surface, combined with black 

 structureless included portions of matter supposed to be car- 

 bon, was to assume that a strong red heat had fused the car- 

 bon, and that, in consequence of subsequent rapid cooling, the 

 cracks in the interior, and, owing to the separation of indi- 

 vidual pieces from the outer surface, the scaly structure, were 

 produced.* The black masses recognisable in the interior are 

 consequently imperfectly fused, condensed, or crystallized car- 

 bon. Now, although it cannot be denied that, as regards the 

 Russian diamonds, there is some probability for the supposed 

 mode of formation, because geognostical investigations have 

 proved the vicinity of dolomite, a rock whose origin is gene- 

 rally believed to be connected with volcanic action, and have 

 shewn the probability of the diamonds having been transported 

 by water, from their original matrix in that substance, to their 

 present situation, not to take into consideration the circum- 

 stance that, according to my own investigations, no well-found- 

 ed objection can be made to the possibility of a fusion (softening, 

 liquefaction) of vegetable carbon under certain circumstances; 

 yet, nevertheless, much may be urged in opposition to Parrot's 

 view. First of all, no signs of volcanic activity are to be met 

 with in the diamor.d districts of other countries, although, in 

 the diamonds produced by them, the same cracks, flaws, and 

 other peculiarities of structure are equally observable ; hence, 

 a diff'erent mode of origin must, at all events, be assigned to 

 the non-Russian diamonds. Secondly, no diamonds have been 

 found actually embedded in the dolomite of the Adolphskoi 

 valley. Thirdly, the presence of internal flaws and cracks, 

 and of the scaly structure of the exterior, by no means neces- 

 sarily involves th(j assumption of great heat and subsequent 

 rapid cooling in the formation of diamonds ; and we may more 



* See PctzholcWs Erdhmde {Geohgk). Leipsic, 1840, p. 189; Petzholclt, 

 de Calamitis et Lithanthracibus. Dresdae et Lipsiae, 1841, p. 31; and Pels- 

 holdt, liber ICulamiten imd Stemko/denbildung. Dresden and Leipsic, 1841, 

 p. 27. 



