the Zeolite Family. 269 



The mineral analysed, thus contained more silica than in the 

 analyses of Vogel and Gmelin. It corresponds, in so far as re- 

 spects that ingredient, more nearly with the formula of Berze- 

 lius. It contained less water than usual 



B. Analcime, Hauy^ — Hexahedral, or Cubic Zeolite, Jameson, 



The last mineral of which I shall at present give an analysis is 

 Analcime, or Hexahedral Zeolite. 



A specimen of this mineral from the Tyrol, was found by 

 Rose * to consist of 



Silica, ... 

 Alumina, . ... 



Soda, 



Water, .... 



99.91 



The formula of Berzelius, N^ Si^ + AZ S^ -f 6 H, gives very 

 nearly the same proportions, viz. 



Silica, 55.17 



Alumina, . . . . 23.27 



Soda, . . . . . 13.87 



Water, 7.75 



A specimen of analcime from Old Kilpatrick, in Dumbarton- 

 shire, I found to be composed nearly in conformity with these 

 proportions ; and after making allowance for the imperfections 

 of analysis, I have no doubt that it had exactly the. same con- 

 stitution as the Tyrol analcime, analysed by Rose. The Kil- 

 patrick analcime was partially crystallized. Its colour was 

 white, with a very pale rose tint. It was translucent on the 

 edges. Fracture uneven. 



After determining the general nature of its ingredients by a 

 preliminary trial, the mineral, in fine powder, was treated with 

 muriatic acid, and the silica separated as usual. The alumina 

 was then precipitated in one analysis by carbonate of ammonia, 

 and in another by caustic ammonia, and its quantity determin- 



• An. de Chimie, et de Phys. xxv. 192. 

 JANUARY— MARCH 1829. T 



