Constituents of various Minerals. 259 



and lime to be only accidental substances, then the mineral 

 would be 2 A / S* + NS 2 , or it would consist of 



2 atoms bisilicate of alumina. 

 1 atom bisilicate of soda. 



There is a slight excess of silica and alumina ; but we have no 

 data to determine its chemical constitution with certainty. In 

 its composition, this stone bears some resemblance to the anal- 

 cime. 



10. Ter silicate of Lime. 



This mineral has been hitherto found only at Gjellebak, four 

 Swedish miles (26| English miles) south from Christiania in Nor- 

 way, in a transition limestone, which extends to the south along 

 the sea-coast. It was taken for a tremolite, till HISINGER sub- 

 jected it to an analysis in 1823, and ascertained its real nature. 

 (Kongl Vetens. Acad. Hand. 1823, p. 177.) 



When occupied about a year ago in arranging my mineral ca- 

 binet, I found among my tremolites a specimen which struck me 

 as peculiar. I requested Mr RICHARD MITCHELL to analyse it. 

 The result was, that it was a tersilicate of lime, in a much purer 

 state than the specimen subjected to analysis by HISINGER. 

 I do not recollect how the mineral came into my possession, and 

 there is no label on the specimen. But probably its locality is 

 the same as that of the tersilicate of lime analysed by HISIN- 

 GER. 



Colour white. 



Fracture fine radiated, giving the mineral a good deal of the 

 appearance of tremolite. The specimen is not crystallised. 



Phosphoresces strongly when rubbed or struck ; but only 

 slightly when heated. 



Easily frangible, and reduced to powder. 



VOL. XI. PART II. L 1 



