Chemical Composition of Amphibole. 





i ■ 



II 



Average 



Eatios 



Si0 2 



56-13 



56-36 



56-25 



•938 



Ti0 2 



•00 







•00 





A1 2 3 



1-24 





1-24 



•0J2 



Fe 2 3 



•74 



•82 



•78 



•005 



FeO 



5-50 







5-50 



•076 " 



MnO 



•48 







•48 



•007 



MgO 



21-18 



21-20 



21-19 



•529 



CaO 



1215 



12-00 



12-08 



•216 



K„0 



•29 



•28 



•28 



•003 



Na 2 



•19 



•18 



•19 



•003 



H„0 



1-89 



1-73 



1-81 



•100 



f: 



•04 







•04 



•001 



33 



Per cents of 

 protoxide bases 



- '938 



•017 



)>-93; 





 56 



23 

 

 



10 

 



65-5 



23-7 



99-84 100-0 



The amount of fluorine in this analysis is so small that a 

 distinct qualitative test could not be obtained. 

 IV. Actinolite from Russell, St. Lawrence 

 Co., New York. Specimen No. 1$]±, Brush 

 Collection. — The specimen chosen for analysis 

 is typical for amphibole found through- 

 out quite an extensive area in St. Lawrence 

 Co. The piece analyzed consists of crystals 

 varying from 2 to 4 cm in diameter, having the 

 forms shown in figure 1, m (110),' e (130), h 

 (010), /' (011), and' occasionally i (031). The 

 color of the crystals is dark green, but small 

 splinters have a rather light color and are transparent. The 

 powdered material floated at 3*102 and sank at 3 - 081, the aver- 

 age being 3*092. The results of the analysis are as follows : — 



Per cents of 

 protoxide bases 



•914 





I 



ii 



Average 



Eatios 



Si0 2 



54-85 



54-75 



54-80 



•913 



TiO„ 



•10 







•10 



•001 



A1A 



2-56 



2-59 



2-58 



•025 



Fe 2 3 



2-40 



2-60 



2-50 



•016 



FeO 



4*68 



4-82 



4-75 



'066 " 



MnO 



trace 







trace 





M^O 



20-24 



20-36 



20-30 



•507 



CaO 



12-19 



11-97 



12-08 



•216 



K 2 



•24 





•24 



•003 



Na 2 



•82 





•82 



•013 



H„0 



1*56 



1-64 



P60 



•088 



f; 



•77 





•77 



•020 j 



Loss at 



110° 





•l 1 







100-65 











= F 2 



•32 





•041 



^•913 



•30 



55-9 



23-8 



0-3 



1-4 



9-1 



2-2 



632 



25-5 



100-33 



Am. Jour. Sci. — Fourth Series, Vol. XXIIT, No. 133. 

 3 



100*0 



-January, 19CJ 



