448 DR T. THOMSON'S Analysis of some Minerals. 



2. Hydrolite. 



This mineral seems to have been first discovered by LEMAN, 

 in the cavities of amygdaloidal rocks, in the Vicentine. These 

 specimens were analyzed by VAUQUELIN, under the name of Sar- 

 colite ; and HAUY considered them as mere varieties of analcime. 

 Some years ago the mineral was discovered in the county of An- 

 trim, Ireland, lodged in amygdaloidal rocks, precisely as in the 

 Vicentine. The specimens in my possession were procured from 

 PATRICK DORAN, an Irish mineral-dealer, who had collected 

 them in this locality. Dr BREWSTER gave an account of the 

 physical properties of this mineral in his scientific Journal *, un- 

 der the name of Gmelinite ; and HAIDINGER has described it un- 

 der the same name, in an appendix added to his English transla- 

 tion of MOHS' Mineralogy f. 



Colour snow-white. 



All the specimens which I have seen, 

 are in double six-sided truncated pyra- 

 mids, with a short six-sided prism between 

 them. The inclination of y on y', accord- 

 ing to Dr BREWSTER'S measurement, is 

 83 36'. 



Translucent. 



Hardness 3.5. Scratches calcareous spar, but not fluor-spar. 



Lustre vitreous. 



Specific gravity 2.054. 



Very easily frangible. 



Before the blowpipe, swells out and assumes the appearance 

 of an enamel ; but does not fuse into a transparent glass. 



* Vol. ii. p. 262. f Vol. iii. p. 174. 



