238 W. LINDGREN — CALIFORNIA GOLD-QUARTZ VEINS. 



but it should be bornig in mind that the existence of this salt has never 

 been proved. It appears that the mentioned facts are sufficient to show 

 that the mineral waters, once circulating in the quartz veins of California, 

 may easily have held gold in solution.* It seems of questionable use to 

 speculate on the particular combination in which the gold is contained in 

 the water, for, according to the views of modern chemistry, watery solu- 

 tions, when sufficiently diluted, contain the solids in a state of dissocia- 

 tion, so that it is uncertain whether salts of gold could exist as such in 

 the always much diluted natural solutions. 



The precipitation of the solids contained in the solution could have 

 been brought about by many means, such as diminution of pressure, dilu- 

 tion, etcetera. The reducing influence of carbonaceous slates, so often 

 maintained as the probable cause of the precipitation of the gold, appears 

 of questionable importance. Veins entirely in massive rocks and far 

 away from any sedimentary areas show too much similarity with those 

 in such areas to attribute a paramount weight to this argument. 



Comparison with Quicksilver Deposits. 



There are certain interesting analogies between the gold-quartz veins 

 of the Sierra Nevada and the quicksilver deposits of the Coast ranges. 

 In the Sierra Nevada the association of minerals is native gold with 

 predominating quartzose gangue ; carbonates in the wall-rocks ; next in 

 importance, iron-pyrites with smaller quantities of the minerals of cop- 

 per, lead, zinc, arsenic, and antimony ; quicksilver-ores are occasionally 

 present. In the Coast ranges we have quicksilver in predominating 

 quartzose, and to some extent carbonate gangue ; next in importance, 



* These reactions are of course by no means the only ones which are likely to take place. It is 

 thus very likely that the reactions established by C. Newbery (Trans. Roy. Soc. Victoria, vol. ix, p. 

 754) have taken place. According to him, the iron is contained as ferrous carbonate with sulphates ; 

 chloride of gold can be held in such very diluted solutions in presence of alkaline carbonates and 

 excess of CO2. "This is true of chloride of gold, and if the sulphide is required in solution, it is 

 only necessary to charge the so]uM)n with an excess of H2S. In this manner both sulphides may 

 be retained in the same solution, depositing gradually with the escape of the carbonic acid." It 

 does not seem probable, however, that sulphates have played a very important part in the chem- 

 istry of the gold veins. The explanation of Phillips for the contemporaneous deposition of gold 

 and pyrites (Proc. Roy. Soc. London, vol. xvi, 1868, p. 294) was that as gold is soluble to some extent 

 in ferric sulphate, solution of this salt containing gold was transformed by a reducing agency into 

 pyrites, the gold at the same time being reduced to the metallic state. The presence of a ferric 

 salt in deep-seated waters would be a very unusual occurrence. The presence of ferrous sulphate, 

 on the other hand, in solution carrying gold does not appear possible, for the latter would be imme- 

 diately precipitated. The fact that in the gold-quartz veins silver occupies such a subordinate 

 position would seem to lend strength to the view that the solutions once circulating in them were 

 not adapted for the dissolving of silver compounds. While thus G. F. Becker found that PbS and 

 Ag2S were insoluble in sodic sulphide, sodic sulphydraie or in solution of sodic carbonate partly 

 saturated with hydrogen sulphide, these salts or metallic silver may be soluble to a very slight 

 degree when in combination with other compounds. An alloy of much gold with slight amount of 

 silver may thus be soluble. I do not know of any experiments on this subject. Doelter, referring 

 to the dissolving action of sodic silicate and carbonate on silver, remarks that it is " hardly " 

 attacked, thus implying some action. 



