PHYSIOGRAPHY. 275 



Idocrase. 



curs here in crystals several inches long, by half an inch in diameter ; 

 but oftener in very minute prisms. In both cases, the prisms are defi- 

 cient in regular, terminating planes, though they commonly have their 

 acute lateral edges bevelled. It is associated with Brucite, and is not 

 .bundant. 



HYPOCHLORITE. (See Green Iron-Ore.) 

 HYPOSKLERITE. (See Feldspar.} 

 HYPOSTILBITE. 



Massive : in globules, consisting of delicate fibres, or impalpa- 

 ble. 



Lustre feeble. Color while. 



Does not scratch glass. Sp. gr. =2-14, 



1. Before the blow-pipe, it melts with difficulty upon the edges; the 

 mass swelling and becoming rough. Soluble in the acids without form- 

 ing a jelly. The solution furnishing a precipitate by oxalate of ammonia. 



2. Analysis. 



By BEUDANT.* By Du MENIL. 



Silica - - - 54-43 - - - 52-25 



Alumina - - - 18-32 ... 18-75 



Lime 8-10 - - - 738 



Soda 2-41 - - . - 2-39 



Water - - - 18-70 - - - 18-75 



3. It has been found with Stilbite and Epistilbite, in amygdaloid, from 

 Faroe. 



4. The above description is quite inadequate for the distinction oi this 

 mineral from Mesotype, 



ICE-SPAR. (See FELDSPAR.) 

 IDOCRASE. Pyramidal Garnet. MOHS. 

 Primary form. Right square prism. 



