392 Penfield and Minor — Chemical Composition and 

 SchnecJcenstein, Saxony. 



Ratio. 



SiO 

 A 



F 



II 



A1.0,- 

 F 



32-82 

 55-41 



•547 

 •543 



18-50 -974 ) nhfi 



0-... -93-5-9= -103 \ ,#P77 



1-00 



roo 



1-97 



107-66 

 O. equivalent to F. 7*80 



99-86 



Stoneham, Maine. 





I. 



II. 



Average. 





Theory for 

 [Al(FOH)] 2 Si0 4 

 Ratio. F: OH = 9:1. 



SiO, .. 



32-28 



32-40 



32-34 





•539 0-99 32-68 



A1,0, . 



56-33 



56-33 



56-33 





•552 101 55-56 



F 



18-56 



18-30 



18-43 



•970 ] 





H„0__ 



1-04 



•93 



•98-4-9 = 



•no 



-1-080 1-98 . 98 



108-08 

 O. equivalent to F. 7*76 



100-32 



107-85 



7-85 



100-00 



Brazil. 



Si 9 0. .. 32-53 

 A1„0 3 __ 55-67 

 F , 15-48 

 H 5 __ 245-4-9= 



Ratio. 

 •542 1-00 

 •546 1-00 



'*™ | 1-087 2-01 



Theory where 

 F:OH=3: 1. 



3279 



55-74 



15-57 



2-45 



106-13 

 O. equivalent to F. 6 52 



106-55 

 6-55 



99-61 



100-00 



From the results of these analyses it is evident that fluorine 

 has been replaced by hydroxyl and the ratios indicate very 

 clearly that SiO, : Al a O, : F-t-OH = 1:1:2 as required by 

 either of the following formulas [A1(F. OH)] a SiO, or [A1(F. 

 OH) 5 ] AlSi0 4 . The first two analyses show very little 

 hydroxyl, so that the material may be regarded as practically 

 the pure fluorine compound, (AlF) 2 Si0 4 . In addition to the 

 complete analyses, isolated determinations have been made on 

 material from the other localities mentioned on page 390 and 

 these results will be given beyond in tabular form. 



