R. B. Riggs — Composition of TourmaMne. 



43 







Dekalb. 



Gouverneur. 



Hamburg. 





'~ 



I. II 





I. 



II. 





I. II. 



SiOo 



36-88 





37-39 



37-33 



-37-45 



35*25 





A1 2 3 



28-87 





27-79 







28-49 





Fe 2 3 



— 





•10 







none 





FeO 



•52 





•64 







•86 





Ti0 2 



•12 





1-19 







•65 





P 2 5 



undet. 





none 







trace 





MnO 



none 





none 







none 





CaO 



3-70 





2-78 







5-09 



" 



MgO 



14-53 





14-09 







14-58 





SrO 



trace 





trace 







trace 





BaO 



none 





none 







none 





Li 2 



trace 





trace 







trace 





Na 2 



1-39 





1-72 







•94 





K 2 



•18 





•16 







•18 





H 2 



3*56 



3-55-3-57 



3-83 



3-77- 



3-89 



3-10 



3-02-3-18 



B 2 3 



10-58 



] 0-46-10-70 



10-73 



10-63- 



-10-83 



10-45 





F 



•50 

 100-83 





trace ? 

 100-42 







•78 

 10037 





Less oxygen 



•21 











•33 





100-62 



100-04 



For the Dekalb and Hamburg tourmaline I am greatly in- 

 debted to Mr. G. F. Kunz. The Gouverneur material was from 

 the National Museum collection. 



From the large amount of titanic oxide found in the Gouvern- 

 eur specimen, it was feared that it might be there as an impurity. 

 Mr. Diller kindly examined a section microscopically and found 

 it, on the contrary, to be quite free from inclusions of any kind. 

 Specimens, from other Gouverneur localities, viz : from the town 

 of Gouverneur itself and from Reese's farm, seven miles to the 

 northward, were also found to contain the oxide in large amounts. 



Orford, "N. H. Dark brown crystals in chloritic schist. 

 Easily fusible. 



f s ; Monroe, Ct. Dark brown crystals in chloritic schist. Easily 

 fusible. 





Oxford. 



i. 



II. 



Monroe. 





Si0 2 



36-66 







36-41 





A1 2 3 



32-84 







31-27 





Fe 2 3 



none 







none 





FeO 



2-50 







3-80 





Ti0 2 



•23 







1-61 





P 2 5 



none 







trace 





MnO 



trace 







trace 





CaO 



1-35 







•98 





MgO 



10-35 







9-47 





Sr,0 



trace 







trace 





BaO 



none 







Done 





Li 2 



trace 







none 





Na 2 



2-42 







2-68 





K 2 



•22 







•21 





H 2 



3-78 



3-77- 



-3-79 



3-79 



3-76-3-82 



B 2 3 



10-07 



9-86- 



-10-28 



9-65 



9-57-9-73 



F 



trace 







none 





10042 



99-87 



