sosman: metasilicate minerals and rocks 



55 



existing data indicate that these metasilicates do not react with 

 one another to form any compound that can not be represented 

 in terms of the components, nor do they appear to dissociate to 

 any appreciable extent into their constituent oxides. We may 



1385V 



1391° Dl 



1537V 



CaSiO 



Fig. 1. Diagram of analyses of minerals and rocks in the 3-component sys- 

 tem MgSi0 3 -CaSi0 3 -FeSi03. Black dots are mineral analyses; circles are rock 

 analyses. EN, enstatite; HY, hypersthene; G, grunerite (amphibole); HE, 

 hedenbergite; W , wollastonite; DI, diopside; E, eutectic; S, solid solution. 



assume for the present, then, that up to at least 1600° and at ordi- 

 nary pressures they form a true 3-component system. 



The material for the diagram consists of analyses of pyroxenite 

 rocks and pyroxene minerals from the tables of Dana, Clarke, 

 Washington, Wahl, and a number of scattered sources. The data 

 are not claimed to be complete. 



The analyses have first been calculated to molecular- percent- 



