Composition of Staurolite. 



made in all cases, as loss by ignition would naturally give too 

 low results, owing to the oxidation of the ferrous iron. 



Analytical results. — The results of the analyses are given 

 below, together with the specific gravity determinations which 

 were made very carefully by means of the pyconometer. 



St. Gothard, Switzerland. 



Specific gravity = 3*748. 



I. II. Average. 



SiO„ 27-80 27-05 27"73 



A1 2 3 __ 53-23 53-35 53'29 



Fe„0 3 2-83 2-83 2-83 



Feb 11-21 11-20 11-21 



MnO -63 -44 -53 



Ms;0 ._ 1-77 1-85 1-81 



IFO 2-19 2-19 



99-59 



Windham, Maine. 

 Specific gravity = 3 '728. 



I. II. 



SiO„ 27-81 27-88 



A1 2 3 ....... 54-44 54-51 



Fe„0 3 2-81 2-90 



FeO 10-52 10-85 



MnO -59 -62 



MgO 1-83 1-87 



ELO 2-24 



III. 



Average, 





27-84 



54-36 



54-46 



2-80 



2-83 



10-44 



10-60 



•56 



•59 







1-85 







2-24 



Specific gravity 



Lisbon, New Hampshire. 

 = 3-775. 



SiO„ 27-81 



A] o 3 . 54-09 



Fe 2 3 2-76 



FeO 12-48 



M<jO 1-92 



ELO 1-70 



100-41 



Burnsville 

 Specific gravity = 3-773. 

 I. 



SiO„ 27-80 



A1 2 3 53-09 



Fe 2 3 4-81 



FeO 9-70 



MnO -27 



MgO 2-64 



HO 1-99 





100-76 







i, North 



Carolina 







II. 



III. 



IV. 



Average. 



27-65 



27-59 



27-77 



27-70 



5330 





53-27 



53-22 



4-81 



4-83 



4-85 



4-82 



9-68 



9-74 



9-79 



9-72 



•38 



•33 



•36 



•34 



2 65 



2-70 







2-66 



1-96 











1-97 



100-43 



