JOUENAL 



OF THE 



EOYAL MICROSCOPICAL SOCIETY. 



DECEMBER, 1905. 



TRANSACTIONS OF THE SOCIETY. 



VII. — Notes on " Arayotite" a Rare California Mineral. 

 By Henry G. Hanks, Corr. F.R.M.S. 



(Read October 18th, 1905.) 



It is a very interesting and singular fact, and one I believe not 

 generally known, that hydrocarbon minerals are almost uni- 

 versally associated with the ores of quicksilver in all parts of 

 the world. The Idria mine in Austria, the Almaden in Spain, 

 and the Huancavelica in Peru, great historical mines, all contain 

 mineral hydrocarbons in some form. The numerous quicksilver 

 mines of California are not only not exceptions, but bitumen is 

 more abundant in them than elsewhere. In some California 

 mines the quantity is so great as to materially interfere with the 

 metallurgy of the ores. We have in California one locality where 

 gold, cinnabar, metacinnabarite, native mercury, pyrite, stibnite, 

 and bitumen are associated in a coating lining rock cavities; at 

 another a jet of natural gas, which had been burning for many 

 years, was extinguished by the superintendent of an adjacent 

 quicksilver mine, who informed me that he found crystals of 

 cinnabar lining the throat of the opening through which the gas 

 escaped ; these he scraped off and re-lighted the gas. Some 

 months after he again extinguished the flames, and found a new 

 and copious crop of crystals. This statement I have no reason to 

 doubt. 



In this connection there are several points of special interest. 

 The reason of the almost universal presence of bitumen in quick- 

 silver mines has never been explained, and the question, What 

 part do the minerals cinnabar, stibnite, bitumen, and in some 



Dec. 20th, 1905 2 z 



