SILICON. 185 



more abundantly at Catherinburgh, in Siberia. 

 It has a rose red colour, and has never been ob- 

 served crystallized ; but it has a foliated fracture, 

 and natural cleavages, indicating a rhomboid for 

 its primitive form. Its specific gravity, as deter- 

 mined by Hisinger, is 3*5384. 



This mineral was analyzed by Ruprecht, and 

 likewise by Napioni ; but at a time when the 

 chemical knowledge of manganese was not far 

 enough advanced to admit of correct results. 

 It was analyzed by Berzelius in 1806, and the 

 constituents were published by him in the first 

 volume of the Afhandlingar (p. 108). He re- 

 peated the analysis in 1817, with as much care 

 as possible, and obtained the following consti- 

 tuents : 



Silica . . . 48 



Deutoxide of manganese 54-42 



Lime . . . 3-12 



Magnesia . . . 0-22 

 With a trace of iron. 



105-76 



Here the weight of the ingredients exceeds the 

 weight of the original specimen by 5'76. The 

 reason is obviously, that, in the mineral, the man- 

 ganese exists in the state of protoxide ; but it 

 was converted into deutoxide in the course of 

 the analysis. It will be shown hereafter, that 

 protoxide of manganese weighs 4%5, and deutox- 



