432 WATSON : VANADIUM and chromium in rutile 



ash of some plants, and in some natural waters. From avail- 

 able data it seems probable that chromium is more widely dif- 

 fused than vanadium, Clarke's estimate in 1900 for the lithosphere 

 being 0.01 per cent. It is common in some meteorites, but is 

 most important in subsilicic rocks like peridotites and the serpen- 

 tines derived from them, present in the form of the magmatic 

 mineral chromite. 



Both vanadium and chromium are not uncommon constituents 

 in heavy ferric silicate minerals, such as some pyroxenes, amphi- 

 boles, and dark micas (biotite). 6 They have long been known in 

 titaniferous magnetites. 7 



Altho vanadium was reported in rutile from St. Yrieux 8 in 

 1859 and chromium in a Swedish rutile from Karingbricka* as 

 early as 1803, their presence in analyses of rutile and ilmenite 

 are rarely indicated. Examination of the available analyses of 

 rutile shows that with but few exceptions the oxides of titanium 

 and iron, the latter usually reported as ferrous oxide, are the only 

 constituents present. These to be sure are the chief constituents, 

 but in light of recent investigations of rutile from various locali- 

 ties in the United States and Europe, vanadium is quite constantly 

 present in variable small quantity, and in a majority of them chro- 

 mium is also found. 



By methods of spectrum analysis Hasselberg 10 in 1897 reported 

 the presence of vanadium in 12 rutiles from localities in the United 

 States, Spain, Germany, France, Switzerland, Russia, Norway, 

 and Sweden. Vanadium was not detected in anatase from Swit- 

 zerland. Hasselberg also reported the presence of chromium in 

 10 of the 12 rutiles examined, it being absent in anatase from 

 Switzerland and Magnet Cove, Arkansas. It is a noteworthy 

 fact that of the 22 analyses of rutile quoted by Hintze 11 neither 



6 Hillebrand, W. F., Loc. cit. 



7 Walz, Isidor, Amer. Chemist, 6: 453-456. 1876; Kemp, J. F., 19th Ann. Rept. 

 U. S. Geol. Survey, Pt. Ill, 387-397. 1897-98. 



8 Deville, H., Sainte-Claire, Comp. Rend., 49 : 301. 1859. 

 • Dana, E. S., A System of Mineralogy, p. 239. 1900. 



10 Hasselberg, B., Astrophysical Journal 6: 22-26. 1897. Also Chem. News, 

 76:102-104. 1897; see also Giles, W. B., Chem. News, 67: 137. 1897. 

 M Hintze, C, Handbuch der Mineralogie, p. 1622. 1907. 



