fJ^^^.A. 



PROCEEDINGS 



OF THE 



KOYAL SOCIETY OF EDINBURGH. 



VOL. III. 1850-51. No. 40. 



Sixty-eighth Session. 



Monday^ 2d December 1850. 



Sir T. M. BRISBANE, Bart., President, in the Chair. 



The following Communications were read : — 



1. Description and Analysis of Gurolite, a new Mineral 

 Species. By Dr T. Anderson. 



The mineral described and analysed by the author was found at 

 Stow, in Skye, where it occurs associated with apophyllite, stilbite, 

 and other zeolitic minerals. It is found principally in a compact 

 basalt, different from that in which these minerals are most abun- 

 dant, and which appears to have been produced by a different eruption 

 of basaltic matter. 



Gurolite occurs in the form of radiated crystalline masses with a 

 fine lustre. It cleaves readily parallel to the plates of which the 

 concretions are composed, and its hardness is about 3. Before the 

 blow-pipe alone it swells up, loses water, and finally fuses with some 

 difficulty into an opaque glass. Its analysis leads to the chemical 

 formula 2 (Ca O Si O3) + 3 HO. 



The author referred to the relations which this mineral bears to 

 the other silicates of lime, of which three are already known, the 

 names and formulae of which are as follows : — 



VOL. III. A 



