(54 Chemical Examination of American Minerals. 



Silica, - - 40-89 



Lime, ._____- 36*56 



Protoxide of iron, ----- 18'33 



Alumina, ______ 5'67 



Water, - 0-60 



101-05 



It would seem from this analysis, to be a compound of, 

 5 atoms silicate of lime, - _ _ - 27*5 



2 atoms bisilicate of iron, _ _ - - 17'0 



1 atom silicate of alumina, - - - - 4*25 



48-75 



The difference between this mineral and common idocrase, 

 consists chiefly in a portion of the alumina being replaced by 

 protoxide of iron. 



Note. Specimens of this mineral, which T received from 

 Dr. C. A Lee, (who first discovered it at Salisbury) were 

 crystalized in rhomboidal dodecahedrons, truncated upon all 

 the edges. So that, notwithstanding the habitudes of the 

 mineral before the blow-pipe, I concluded it to be a variety 

 of garnet. It has a strong resemblance to the amber-colored 

 garnet, lately found by Dr. Webster in Carlisle, Massachu- 

 setts, and like that mineral fuses easily into a transparent 

 glass. Dr. Thomson's analysis, however, would seem to 

 make the Salisbury mineral idocrase, if the composition alone 

 be regarded. 



