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UNIVERSITY OF VIRGINIA PUBLICATIONS 



of alightgraynearlj' white substance, sometimes stained with iron oxide, 

 having high refraction and double refraction, and can probably be referred 

 to hj'drargillite as suggested by Rosenbusch.* The common mineral asso- 

 ciates of the lazulite in thin sections are quartz, cyauite, rutile, and musco- 

 vite. These may be discerned megascopically in the hand specimens. 



In the following table are given the analysis of the lazulite from Georgia, 

 and analyses of lazulite from North Carolina, Canada, and Sweden : 



Analyses of Lazulite froiti Graves Mountain, Lincoln County, Georgia,and other localities. 



PsOt ; 38.25 



AI2O3 1 33.92 



FeO.. 

 MgO. 

 CaO., 

 H,0.. 

 SiO... 



3.99 

 9.08 

 3.12 

 0.83 

 6.05 



Specific gravity.. . 



100.24 

 2.958 



40.57 

 35.97 

 4.23 

 9.63 

 3.31 

 6.21 



100.00 



284 

 353 



58 

 241 



59 

 350 



1 



1.2 



43.76 

 31.70 

 8.17 

 10.04 



5.59 

 1.07 



100.33 

 3.122 



42.52 

 32.86 

 10.55 



8.58 



trace 



5.30 



99.81 

 2.78 



vt 



46.39 

 29.14 

 2.09 

 13.84 

 2.83 

 6.47 



100.76 

 3.045 



* MnO — trace. 



t Deducted 3 per cent S1O2. 



I corresponds to the formula 



(Fe, Mg, Ca) O.AI.Os.PjOs.H^O 

 FeO: Mg(Ca) = 1:5 

 MgO: CaO = 1:3 



I. Lazulite collected bj' Thomas L. Watson from Graves Mountain, Lincoln Count}', 



Georgia. J. Wilbur Watson, analyst. 

 II. I calculated to Si02 free basis. 

 Ila. Ratios from II. 

 III. Lazulite from Gaston County, North Carolina; average of two analyses. Smith 



and Brush, Ayner. Journ. Sci., 1858, vol. 16, p. 670. 

 IV. Lazulite from Horrsjoberg, Sweden. (Ingelstrom, Journ. pr. Ch., 1855, vol. 

 64, p. 253). Quoted by Dana, E. S., A Systetn of Mineralogy, 1900, 6th ed., 

 p. 799. 

 V. Lazulite fromnear mouth of Churchill River, Keewatin, Canada. Hoffman, Ch., 

 Geol. Surv. of Canada, 1878-79, p. 2. 



Rutile. Knowledge of the occurrence of rutile at Graves Mountain was 

 early made kno-wTi by Professor Charles U. Shepardf who was the first to 



* Rosenbusch-Iddings, Microscopical Physiography of Rock Making Minerals, 1893, 

 p. 236. 

 t Shepard, C. L'., Op. cit., p. 36. 



