674 WATSON AND STEIGERI SPINELLITE FROM VIRGINIA 



the basis of composition of the spinel, the analyses of which show 

 FeO in excess molecularly of MgO. It is essentially negligible 



TABLE 3 



Analyses of Emery from Virginia, New York, and Naxos 



Si02... 



AI2O3. 



FesOs. 



FeO... 



MgO.. 



CaO... 



Na.O.. 



K2O... 



H2O-. 



H2O+. 



Ti02.. 



ZrOa.. 



CO2... 



P2O,.. 



SO3... 



S 



■Cr203. 



NiO... 



MnO.. 



BaO... 



SrO... 



Sp. Gr. 



4.90 

 63.64 

 29.61 

 1.80 

 0.06 

 0.45 



1.04 



0.03 



100.53 

 4.008 



I. Rock emery 1§ miles west of Whittles, Pittsylvania County, Virginia. 

 George Steiger, analyst. 



U. Spinel emery, high grade, Buckbee mine, Westchester County, New York. 

 G. S. Rogers, analyst. Ann. N. Y. Acad. Sci. 21; 64. 1911. 



III. Pure emery, Dalton mine, Westchester County, New York. G. S. Rog- 

 ers, analyst. Ann. N. Y. Acad. Sci. 21: 64. 1911. 



IV and V. Naxischen handelssmirgels nach Oser. S. A. Papavasiliou. Zeitschr. 

 Deutsch. Geol. Ges., 65:87. 



" Average of five determinations made by S. D. Gooch on separate fragments 

 at 24°C. 



in the Naxos emery because of the practical, though not entire, 

 absence of spinel. Ilmenite, present up to 5 or 6 per cent in the 

 emery from Virginia and New York, accounts for the appreciable 



