■914.] HYDROUS CALCIUM VANADATES. 33 



analyses show quite different percentages of lime. This is not sur- 

 prising if we conceive that the vanadium of the patronite has become 

 oxidized to a polybasic acid of quinquivalent vandium, which then 

 was gradually neutralized by calcium. It seems reasonable to expect 

 that ores of all gradations occur from the sulphide patronite to the 

 half neutralized salt hewettite and finally to the fully neutralized salt 

 represented by pascoite (p. 49). Indeed, such intermediate stages 

 are probably represented by a number of the specimens brought from 

 Peru by Mr. Hewett and of which a few analyses are given in his 

 paper. These ores are, for the most part, microcrystalline, though 

 some show distinct evidences of crystallization, as Mr. Hewett 

 pointed out. They are of varying colors, from red through greenish 

 to the black of the original patronite. Some of the specimens are 

 not fully oxidized^ but contain vanadium in a lower state of oxida- 

 tion than corresponds to quinquivalency, and even free sulphur. 

 Some of them are characterized by high iron content and relative 

 freedom from lime, as shown by the following analysis,* which seems 

 to represent essentially a ferric vanadate. 



V=05 57-3 



V,0, 4-8 



M0O3 3-3 



FcaOa 19.6 



TiO^ I 



SiO, 6 



CaO 7 



H,0 13-9 



100.3 



Molybdenum is naturally a characteristic component of the oxi- 

 dation products of patronite since it occurs in the patronite ore. 



Metahewettite. 

 Unlike the Peruvian mineral, the North American vanadate is an 

 impregnation in sandstone, generally coating the sandstone grains, 

 sometimes filling cavities and crevices. The specimens are almost 



2 Analysis I indicates that oxidation is not yet quite complete in our best 

 specimen. 



^ Made in 1907 in the laboratory of the U. S. Geological Survey and 

 quoted by Mr. Hewett, loc. cit., p. 311. 



PROC. AMER. PHIL. SOC. , LUI. 2I3 C, PRINTED JUNE 17, I9I4. 



