Troost on the Pyroxene. 



59 



we shall proceed to give an account of the different species 

 that have been formed from this family. We will call them 



Volcanic Pyroxene. 



Augite 



Coccolite 



Sahlite 



Baikalite 



Fassaite — — 



Sherzolite 



Diopside 



Mussite 



White 



1. Volcanic P.* It occurs in small and moderately sized 

 regular crystals, or in grains which are sometimes insula- 

 ted or sometimes combined and dispersed, or disseminated 

 through lava or rocks. Different analyses have been made 

 of it. — It is composed 



Etna. Frascati. Rhinberg. 



Vauquel. Klaproth. Klaproth. 



52.50 48 52 



10 8.75 12.75 



3.30 5 5.75 



13.20 24 14 



14.66 12 12.25 



2 1 0.25 



trace 



0.25 



4 



Tromsdorf found in the Pyroxene of the Etna 5.18 pot- 

 ash. Klaproth detected also a small quantity in those of* 



• Schorl noir en prisme octaedre Rome de L. Schorl volcanique, 

 Bergm. Vokanilc and Virescite, Lamethric. Augite, Werner. Ai"j!'r 

 Jameson. 



Silex, 



Magnesia, 



Alumine, 



Lime, 



Iron, 



Manganese, 



Potash, 



Water, 



Loss, 



