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NEW YORK STATE MUSEUM 



Silver Ag 



Silver is found in nature quite pure though sometimes alloyed 

 with gold, copper and other metals. Isometric crystals are of 

 rather more frequent occurrence than in the case of gold; 

 parallel groupings of cubes are quite common; these pass into 

 distorted fernlike and wirelike forms similar to those shown in 

 pi. 12 2 . Silver is a soft, malleable metal, silver-white on the 

 fresh fracture but tarnishing to dark gray or black. 



Silver occurs in veins traversing gneiss, schist, porphyry and 

 other rocks and is also associated with copper in calcite. It is 

 commonly carried in small amounts by galena. Some of the 

 more important localities where it is found are Kongsberg, 

 Norway; Saxony; Peru; northern Mexico; also Michigan, Col- 

 orado, Idaho, Montana and Arizona. An unsuccessful attempt 

 to mine silver in the vicinity of Ossining was made early in the 

 last century. 



Silver is used for much the same purposes as gold. 



Copper occurs in soft, red, malleable crystals of the isometric 

 system, disseminated masses and sheets. The common crystal 



former often tarnished nearly black. 



Copper occurs in beds and veins with native silver and the 

 various copper ores and is frequently found near dykes of 

 igneous rock. In the Lake Superior region in northern Michigan 

 it occurs in dolerite and sandstone associated with calcite, dato- 

 lite, analcite, etc. 



Copper is largely used in electric work and in alloys such as 

 brass, bronze, bell metal, German silver, etc. 



Copper Cu 



Fig. 159 

 Copper 



forms are the cube and tetrahexahedron 

 alone or in combination as shown in 

 fig. 159; distorted and twisted crystals 

 t pass from parallel groups to branching 

 arborescent forms (pi. 13 2 ). Twins are 

 quite common but are, however, almost 

 invariably distorted. The luster is metal- 

 lic and the color and streak red, the 



