II3t 4KALYS1S OF Jade. 



Component X hundred parts of saussurite afforded me 



parts of the 



saassurLie. Silex 44 



iMumine 30 



Lime 4 



Oxide of iron 12*5 



Oxide of manganese 0'05 



Soda 6 



Potash * 0-25 



96-Sr 

 Loss 3-2 



100. 



rt 15 neither a From these results it appears, that the saussurite is not 



jniignesian ^ maonesian stone. It appears too, that it cannot be classed 



stone, nor a. _ " ^'^ ' 



jade. vvith the nephritic jade, as the alumiae, which is in very 



small quantity in the jade, forms a considerable proportion 

 of the saussurite; and the two stones likewise differ greatly 

 in the alkali they contain. 

 The saussurite The saussurite contains a great deal more metallic oxide 

 feldtspa? ^' ^^^*" feldtspar ; their earthy principles however are the same : 

 at least they succeed each other in the same order, the pro- 

 portion of silex only being greater in the feldtspar, and the 

 proportion of alnmine less. Their external characters, if 

 •we consider the extremes of the two species, are totally dif- 

 ferent, but there are gradations between these, that bring 

 Ihera almost together. Thus that feldtspar, which my fa- 

 ther called greasy {Voyages dans les Alpes, § 1304^, and 

 which is found crystallized in the green antique porphyry 

 called ophites, and confusedly crystallized in nodules of va- 

 riolite, does not always exhibit any signs of a lamellar struc- 

 ture, its hardness is so great, that it readily scratches rock 

 crystal ; and like the saussurite it has a greenish and oily 

 aspect. 



If the granulous and scaly petrosilices be feldtspars, as 

 analysis tends to show*, another link is added to connect 

 them. 



* See the analysis and description of the petrosilex of Pisse-Vache. 

 Voyages dans les Alpes, § 1057. 



I do 



