OCCURRENCE OF TINGUAITE AT KOSCIUSKO, N.S.W. 369 



On these assumptions the whole of the material in the rock is 

 exactly accounted for with the exceptions that there remains a 

 residue of about 1 per cent. Na 2 0, and that 0*2 per cent. CaO is 

 required above that present in the rock. This is shown by the table 

 on the next page, in which the percentage amounts of the different 

 ingredients are accounted for, taking the following formulae for 

 • the minerals present : — 



Orthoclase and sanidine (K 2 0. A1 2 3 . 6 Si0 2 ) 



Si0 2 64-75 



A1 2 3 18-35 



K 2 16-90 







100-00 



Albite (Na 2 0. 



A1 2 3 . 



6 SiO*). 



Si0 2 





68-70 



Al.O, 





19-47 



Na 2 





11-83 





10000 



Nepheline (K 2 



,0. 5 Na 



9 0. 6 A1 2 



Si0 2 





41-48 



Al 2 O s 





35-25 



Na 2 





17-85 



K 2 





5-42 





100-00 



JEgirine (Na 2 0. Fe 2 3 



. 4 Si0 9 ). 



Si0 2 





51-95 



Fe 2 3 





34-63 



Na 2 





13-42 





100-00 



RSi0 3 (MgO. 



2 FeO. 3 CaO. 



Si0 2 





5056 



FeO 





20-22 



MgO 





5-62 



CaO 



■ • • • • • 



23-60 





10000 



MnSi0 3 (MnO 



. Si0 2 ). 





SiO, . 





46-15 



MnO . 





53-85 



12 Si0 2 ). 



100-00 



X— Dec. 4, 1901. 



