292 ECONOMIC GEOLOGY 



Importance is also attached to the discovery of platinum in 

 association with several copper minerals, as covellite, the sulphide 

 of copper, CuS. This result may lead to the discovery of 

 platinum in other members of the copper group. 



The average price paid for platinum in 1912 was $45.55 per 

 Troy ounce as compared with $43.12 in 1911 and $32.70 in 1910. 

 With this higher price for platinum it is rational to expect a 

 persistent search for platinum ores in the placer gravels of 

 serpentine rocks; in the members of the copper group, and in the 

 nickeliferous pyrrhotites. 



The demand for platinum is increasing faster than the supply. 

 The newer requirements in the electrical and automobile-engine 

 industries absorb the metal and remove it from the market 

 entirely. The same is largely the case in the jewelry industry, 

 while the metal used in making chemical ware is largely returned 

 in the form of scrap platinum for manufacture. 



The imports of platinum for 1912 were valued at $3,634,738. 

 No platinum seems to have been re-exported. 



Russia is the world's chief producer of platinum. The metal 

 comes from the Siberian side of the Urals. The production for 

 1912 is estimated at 310,000 ounces. Colombia is the second 

 producer with an output estimated at 12,000 ounces. A small 

 amount of platinum is derived also from Canada, New South 

 Wales, Borneo and Sumatra. 



LEAD 



Production. The value of the output in the lead industry 

 has risen from $23,280,200 in 1901 to $43,280,460 in 1912. The 

 increment of increase has not been steady. In 1908 the produc- 

 tion fell 32.56 per cent, below that of 1907. The lead produced 

 in the United States is derived from various sources and receives 

 different names, dependent upon its source. 



Primary lead signifies lead that has been produced directly 

 from its ores. Secondary lead is derived from scimmings, 

 drosses, old metal, alloys, as babbitt, solder, and type metal. 

 The recovery of lead by refining these materials constitutes an 

 integral portion of the lead industry. The business is mostly 

 carried on by the small refineries scattered over the United 

 States, but the large smelters and refineries working primary 

 lead frequently incorporate material from secondary sources. 



