WATSON: VANADIUM AND CHROMIUM IN RUTILE 



433 



vanadium nor chromium is reported as being present in a single 

 analysis. Of 100 analyses of ilmenites quoted by Hintze 12 Cr 2 3 , 

 ranging from a trace to 0.56 per cent, is reported in 8, and vana- 

 dium is not listed in any. 



In recent investigations of rutile by the Virginia Geological 

 Survey accurate chemical analyses of several rutiles and ilmenite 

 were made, and each analysis agreed in showing the presence of 

 both vanadium and chromium in small and unequal but appreci- 

 able amounts. The results follow in the annexed tabular state- 

 ment. 



Partial chemical analyses of rutile and ilmenite 

 (Wm. M. Thornton, Jr., analyst) 



I. Red rutile from feldspathic facies of syenite, Roseland, Nelson County, 



Virginia. 

 II. Very dark rutile from nelsonite on Warwick tract, If miles northwest of 

 Rose's Mill, Nelson County, Virginia. 



III. Nearly black rutile from Krageroe, Norway. 



IV. Black ilmenite from same locality as II. 



Attention is directed in the analyses to the predominance of 

 vanadium over chromium. Hasselberg 13 found for the rutiles 

 he examined that when vanadium was present in very appreciable 

 amount chromium was also present, but when vanadium was 

 present in very small amount chromium was present either in 

 trace or entirely absent. Altho there are frequent exceptions 

 vanadium is commonly tho but slightly in excess of chromium 

 in the known analyses of titaniferous magnetites. The exact 

 form or combination in which these two constituents are present 

 in rutile is entirely conjectural. As Washington 14 remarks vana- 

 dium probably exists as V 2 3 , replacing A1 2 3 and Fe 2 3 , in ferro- 



12 Hintze, C, Ibid., pp. 1876-1881. 1908. 



13 Hasselberg, B., Op. cit. 



14 Washington, H. S., Trans. A. I. M. E. 39: 756. 1909. 



