Argillaceous Genus. 95 



SPECIES XII. 



Argill united to 2,3, or 8 times Its weight of 

 Silex, about half its 'weight of pure Calca- 

 reous Earth^ and from once to twice its 

 weight of Water, 'without any Iron, except 

 accidentally. 



Zeolyte. 



This ftone is found of different degrees of 

 tranfparency, or perfectly opake, either co- 

 lourlefs, whitifh, yellowifh, greenifh, or red- 

 difh ; its fhape is either pyramidical, colum- 

 nar, tabular, oval, capillary, or amorphous ; 

 its texture either granular, fcaly, or radiated ; 

 the filaments diverging as from a central 

 point, or indiftinguifhable. 



It does not give fire with fteel. 



Its fpecific gravity is from 2,1 to 3*15* but 

 this laft is very rare. 



It does not eflervefce with acids, though it 

 is partially foluble in them, but if inferted 

 into a proper proportion of concentrated ni- 

 trous acid, it forms a .gelatinous mafs, arifing 

 from the fufpenfion and diffufion of the fill- 

 ceous Earth contained in it ; but this property 

 is not peculiar to zeolyte, as Mr. Pdlatier has 



fliewn, 



