64 



NEW YORK STATE MUSEUM 



Salt is of wide distribution and frequently occurs in beds of 

 sufficient size to constitute a true rock mass. These deposits, 

 which arc found interstratified with rocks of all geologic 

 horizons, have been formed by gradual evaporation from bodies 

 of water which have been cut off from the main body of the 

 ocean, or which, as in the case of Great Salt lake and the Dead 

 sea, have been concentrated through lack of an outlet. The 

 mineral matter is crystallized out in inverse ratio to its solu- 

 bility, the less soluble minerals, such as gypsum, forming prior 

 to the more soluble ones such as salt. This process is still tak- 

 ing place in many parts of the world. 



Halite is of of such universal occurrence that a list of its local- 

 ities would include almost every civilized country. In the United 

 States extensive and valuable deposits of salt are found in 

 central and western Xew York, in Ohio, Michigan, West Vir- 

 ginia, Kansas, Louisiana, Xevada. Utah, Arizona and California. 

 Salt springs and wells abound in the neighborhood of the salt 

 deposits and these as well as the waters of salt lakes and sea 

 waters are used as sources of the commercial product. 



Halite is used to form a glaze on pottery and in many chemical 

 and metallurgies industries as well as for the familiar culinary 

 and preservative purposes. 



Cerargyrite (horn silver) AgCl 



Cerargyrite, the chlorid of silver, is composed of 24.7,< chlorin 

 and 75.3^' silver. 



Isometric crystals of a cubic habit are quite rare, the mineral 

 usually occurring in massive crusts or coatings of a grayish 

 green to violet color and waxy or resinous luster resembling 

 horn or wax. It is extremely sectile and turns violet-brown on 

 being exposed to the light. 



Cerargyrite probably results from precipitation from silver 

 charged solutions in contact with the chlorids contained in sur- 

 face waters. It usually occurs near the top of veins in clay 

 slate, associated with other ores of silver. Cerargyrite is found 

 extensively in Peru, Chile and Mexico; it also forms part of the 

 mineral wealth of Colorado. Nevada, Idaho and Utah. 



It is mined for silver. 



