5268 On the Dhcovcnj of Diamonds 



otherwise. The following obsei'vations will assist in determining 

 the point. 



1. The minerals that occur in the descending or mountain al- 

 luvium, viz. the crystals of pure transparent quartz, the brown 

 ironstone and anatase, are sharp-edged, although these latter, 

 owing to their softness, would have been rounded in a very short 

 course ; they have not therefore come from a distance, but must 

 have been derived from the neighbouring rocks. 



2. The loose crystals of pure transparent quartz, and the ana- 

 tase, are derived from disintegrated dolomite ; the first resemble 

 the rock-crystals that occur in blocks of dolomite, and the latter 

 are attached to rock-crystals, as may be distinctly seen in the 

 impressions on the anatase crystals. The balls of calcedony 

 sometimes met with may have lain in the dolomite, for hollows 

 filled by infiltration with quartz occur in it The cubes and 

 grains of brown ironstone are from the foliated limestone, in 

 which indeed they are still found ; the gold and plalina are pro- 

 bably from disintegrated veins of quartz. 



3. The dolomite is probably the repository of the diamond .^ 

 In the same manner as silica, carbonate of lime, and carbonate 

 of magnesia, have separated themselves in the form of rock- 

 crystal and bitterspar, so also might, according to Gobel, the 

 carbon in dolomite separate in the form of diamond. The per- 

 fect form of the diamond crystals is not against this opinion, 

 as we find embedded in the dolomite, single rock-crystals, in 

 which the prisms are acuminated at both extremities. 



It is much to be desired, that the numerous blocks of that 

 black dolomite of the valley of Adolphskoi, which is particu- 

 larly rich in druses of quartz and bitterspar, were carefully exa- 

 mined ; further, that comparative investigations were made on 

 the diamond district, as on the valley of the rivulet of Rudanka, 

 where already Mr Schmid found black dolomite and traces of 

 cold. If it results from these investigations, that diamond ac- 

 tually occurs in dolomite, the following question will have to be 

 decided. 



If the dolomite already described always contains diamond, 

 may it occur in its different formations with or without gold and 

 platina ? Or, if every gold and platina bearing formation is dis- 

 posed to afford diamond, when it contains a carbonaceous rock, 



