86 PHYSIOGRAPHY. 



Okenite. 



Unctuous and tender. Scratched by the nail. Exhales no ar- 

 gillaceous odor when breathed upon. 



1. It increases one tenth in weight from soaking in water. After cal- 

 cination, it is magnetic. 



2. Analysis. 

 By BERTHIER. 



Silica 44-0 



Peroxide of iron 29:0 



Alumina 3-6 



Magnesia - - . - - - 2-1 



Water - - - - 187 



3. It is found in the ore of manganese, worked at the village of Par- 

 doux, in the department of Dordogne in France. It occurs in onion- 

 shaped masses of the size of the fist. 



NOSIAN. (See Sodalite.) 

 NUTTALLITE. (See Scapolite.) 

 OBSIDIAN. (See Pitchstone.) 

 OCTAHEDB.ITE. (See Afiatase.} 



OKENITE. 



In delicately fibrous masses. 



Lustre glimmering, approaching to pearly. Color white, with 

 a shade of yellow or blue. Translucent on the edges. 



Hardness, between Fluor and Feldspar. Sp. gr. =2-28. 

 1. Before the blowpipe, it melts easily into a porcelainous mass. Pieces 

 thrown into muriatic acid, become, after some time, translucent and ge- 

 latinous at the surface, which change, gradually extends through the 

 masses. The powdered mineral is easily decomposed by this acid, the 

 silica appearing throughout the solution in the form of flocculi. 



2. Analysis. 

 By KOBEL.L,. 



Silica - - 56-99 - 55-6-4 



Lime - 26-35 - - 2659 



Water - - 16-65 - 17-00 



Alumina, oxide of iron, and traces of potash, - 0-53 



3. It is found, along with Zeolitic minerals, in amygdaloid in Green- 

 land. 



