GENERAL REMARKS ON ORES. 93 



miner's use of the term it is a mineral substance that yields, by 

 metallurgical treatment, a valuable metal, and especially when 

 it profitably yields such a metal. In the former sense, galena, 

 the common ore of lead, is, if it contains a little silver, an 

 argentiferous lead-ore ; while, in the latter, if there is silver 

 enough to make its extraction profitable, it is a silver ore. 

 Further than this, where a native metal, or other valuable 

 metallic mineral, is distributed intimately through the gangue, 

 the mineral and gangue together are often called the ore of the 

 metal it produces. 



We have beyond to do with ores only in the mineralogical 

 sense. 



Ores are compounds of the metals, not metals in the native 

 state. The more common kinds are compounds of the metals 

 with Sulphur (sulphides) ; with Arsenic (arsenides) ; with Sul- 

 phur and Arsenic (sulph-arsenides) ; with sulphur in ternary 

 combination along with arsenic, antimony or bismuth (making 

 compounds called sulph-arsenites, sulph-antimonites, sulpho-bis- 

 mutites) ; with Selenium (selenides) ; with Tellurium (tellu- 

 rides) ; with Oxygen (oxides) ; with Chlorine, Iodine, or Bro- 

 mine (chlorides, iodides, or bromides) ; with oxygen in ternary 

 combination with carbon (making carbonates) ; with Sulphur 

 (making sulphates) ; with Arsenic (making arsenates) ; with 

 Phosphorus (making phosphates) ; with Silicon (making sili- 

 cates). 



Gold and platinum are, with rare exceptions, found only na- 

 tive, or intimately mixed in essentially the pure state with some 

 metallic minerals. Tellurium is the only acidic element that 

 occurs combined with gold in nature. 



Silver is found in the state of sulphide, antimonide, selenide, 

 telluride, sulph-arsenites and sulph-antimonites, but never as 

 oxide or in oxygen ternary compounds. 



Quicksilver occurs in the state of sulphide (the common ore) ; 

 also in that of selenide and sulph-arsenites. 



Copper and lead occur in the state of sulphides (common ores), 

 and also in all the binary and ternary states mentioned above. 



Zinc is known in the state of sulphide (very common), 

 o&ide, carbonate, sulphate, silicate (all, excepting the sulphate, 

 valuable as ores) ; and Cadmium in that of sulphide only. 



Tin occurs in the state of oxide (the common ore), and sul- 

 phide. 



Cobalt and Nickel occur in the states of sulphide, arsenide, 

 sulph-arsenides, antimonide, oxide, sulphate, arsenate, carbon- 

 ate ; and nickel in that also of a silicate. 



