180 PHYSIOGRAPHY. 



Serpentine. 



1. Serpentine is divided into two subspecies, the common and pre- 

 cious ; the latter embracing those varieties which possess handsome col- 

 ors, and a tendency to conchoidal fracture ; the former includes the 

 duller colors and the slaty varieties. 



2. It hardens on being exposed to fire, and melts only with great dif- 

 ficulty on the edges. 



3. Analysis. 

 By JOHJV. 



Silica 42-50 



Magnesia 38-63 



Alumina 1-00 



Lime . . 0-25 



Oxide of iron . . ! . . . . 1-50 



Oxide of manganese ...... 0-62 



Oxide of chrome ...... 0-25 



Water ,. 15-20 



4. Serpentine forms mountain masses and beds in^primitive rocks, and 

 frequently contains crystals, grains, or compound nodules of various oth- 

 er species. Precious Serpentine, in particular, is often mixed with 

 white limestone. 



5. The different varieties of Serpentine are met with in Saxony, Sile- 

 sia, Austria, Hungary, Stiria* Italy, Corsica, Sweden, England, Scot- 

 land, and other foreign countries. 



Crystallized vaiieties, of a blackish green color, sometimes of conside- 

 rable dimensions, occur at Amity, (N. Y.) disseminated through lime- 

 stone, along with black Spinel arid Ilmenite ; also at Byram, (N. J.) in 

 the same rock with red Spinel. At the last place, the color of the Ser- 

 pentine is oil-green. Serpentine, of a handsome green color, and con- 

 choidal fracture, is found at Newburyport, (Mass.) and at Newport, 

 (R. I.) ; of a very light green color, at Phillipstown, in the Highlands of 

 New York. Extensive formations of Serpentine exist in the neighbor- 

 hood of New-Fane, (Vt.) and of Middlefield, (Mass.) 



SIDERITE. (See Quartz.} 

 SIDEROSCHISOLITE. (See Limonite.) 

 SILICATE OF IRON. 



SILICEOUS OXIDE OF MANGANESE. (See Manganese 

 Spar.) 



