60 SILVER-LEAD DEPOSITS OF EUREKA, NEVADA. 



of iron, with a little lead and silver, which are tolerably rich in gold. There 

 is usually nothing in their appearance to indicate their value, and it is only 

 by constant assaying that it is possible to determine what they are worth. 



Quartz ores, especially those carrying quartz in visible crystals, are 

 uncommon, except in the Eureka Tunnel and some parts of Prospect Mount- 

 ain, but when found they are usually rich in gold and poor in silver and 

 lead. There is a porous crystalline quartz ore found in some places in the 

 Richmond mine, from which assays of over $300 per ton (.04977 per cent.) in 

 gold, with but a few dollars in silver, have been obtained. The sulphuret 

 ores usually consist of a compact mass, composed of pyrite, arsenopyrite, ga- 

 lena, and blende, and vary very considerably in the amounts of silver and 

 gold that they contain. The miners do not as yet distinguish different va- 

 rieties by name. 



Analysis of Richmond ore. — The following analysis of ore from the Richmond 

 mine for the year 1878 will serve as an example of the ores from all the 

 mines of Ruby Hill, which greatly resemble each other both as regards 

 quality and the minerals which compose them. The sample analyzed was 

 an average of all the Richmond ore worked at the furnaces of that com- 

 pany during the previous year, and the analysis was made by Fred. Claudet, 

 of London." 



Per cent. . Per cent. 



Lead oxide 35.65 Lead 33.12 



Bismuth 



Copper oxide 15 Copper 12 



Iron protoxide 6 34.39 Iron 24.07 



Zinc oxide 2.37 Zinc 1.89 



Manganese oxide 13 



Arsenic acid 6.34 Arsenic 4.13 



Antimony ... .25 Antimony 25 



Sulphuric acid 4.18 Sulphur 1.67 



Chlorine 



Silica 2.95 



Alumina 64 



Lime 1.14 



"Copied, by permission, from the records of the company. 



l In this analysis the iron is represented in the form of protoxide, whereas it occurs as sesqui- 

 oxide. That it was intended to give it in the form of sesquioxide is shown by the percentage of iron 

 (24.07) given would correspond with 34.39 of sesquioxide. 



