HEWETTITE, METAHEWETTITE AND PASCOITE, 

 HYDROUS CALCIUM VANADATES. 



By W. F. HILLEBRAND, H. E. MERWIN and FRED E. WRIGHT. 



Introduction. 



(Read April 25, 19 14.) 



Some years ago, Mr. D. Foster Hewett, in a paper^ on the re- 

 markable vanadium locality of Minasragra, Peru, described briefly 

 certain oxidation products of the vanadium sulphide ore, patronite, 

 which he was inclined to regard as vanadic acids, although the opin- 

 ion of one of us (H.), based on preliminary analyses, was that two 

 of the minerals were calcium vanadates. 



Several years later the chief constituent of a certain red ore of 

 vanadium from Paradox Valley, Montrose County, Colorado, was 

 identified (H.) as a calcium vanadate, seemingly identical with one 

 of those from Peru. Since then this red ore has been found over 

 a wide area, extending into Utah. A good deal of additional chem- 

 ical work has been done intermittently during the past three years upon 

 material of both occurrences and it has been studied microscopically. 

 It has developed that, although the minerals are deceptively alike in 

 appearance and general behavior and have the same empirical for- 

 mula, they seem to be specifically distinct, are probably in fact isomers. 

 The Peruvian mineral, the first known and studied, we are pleased 

 to name hezvettite, after Mr. D. Foster Hewett, now of the U. S. 

 Geological Survey, who has done so much to make the Minasragra 

 occurrence known. Its isomer may appropriately be called meta- 

 hewettite. It is probable that hewettite occurs also in Paradox Val- 

 ley (see under metahewettite, pp. 37-38). 



The detailed results of the several authors' work are submitted in 

 the following pages, a preliminary announcement having appeared 

 in the Jour. Washington Acad, of Sci., j, 157, 1913. 



1 Trans. Am. Inst. Min. Eng., 40, 291, 1909. 



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