I9I4-] HYDROUS CALCIUM VANADATES. 49 



description^^ of a dark red, silky, soft and dense, moss-like mineral 

 to which he assigned the formula V^O^fH^O. The description fits 

 hewettite very well in the main and it will be of interest to learn if 

 on further study alaite may not prove to be a calcium vanadate re- 

 lated to, if not identical with, hewettite or metahewettite. Alaite is 

 one of a number of vanadium and uranium minerals occurring in 

 the Province of Ferghana, Russian Turkestan. 



Pascoite. 



Not observed in the surface deposit at Minasragra, Peru, but 

 formed on the walls of an exploratory tunnel since its excavation, is 

 a mineral representing a further stage of neutralization by calcium 

 than is shown in hewettite. The specimens examined were among 

 those brought from Peru by Mr. Hewett and the analysis given below 

 was made several years ago in the laboratory of the U. S. Geological 

 Survey. The name proposed, pascoite, is from Pasco, the province 

 in which the locality of occurrence lies. 



Crystallographically, this mineral is unsatisfactory, since it occurs 

 only in minute grains and clusters of grains, arranged in a way indic- 

 ative of a crustaceous deposit — as though they were secondary in 

 origin and had been precipated as a crust about preexisting masses. 

 No well-developed crystals suitable for goniometric measurement 

 were observed, and only here and there in the crystalline aggregates 

 were minute crystal faces seen. No distinct cleavage was noted, al- 

 though occasionally indications of an imperfect pinacoidal cleavage 

 were observed in grains under the microscope. The fracture is con- 

 choidal. In color this mineral ranges from dark red-orange to yellow- 

 orange; the more homogeneous masses being uniformly red-orange 

 throughout. In thin flakes it is translucent and the clearer individ- 

 uals are vitreous to subadamantine in luster, especially on flat crystal 

 faces which glisten here and there in the aggregate. The streak is 

 cadmium-yellow and the hardness about 2.5. The specific gravity 

 is about 2.457, determined in methylene iodide and benezene, on the 

 clearest and most homogeneous material. This value may be slightly 

 low because a crystalline aggregate, instead of a single crystal, was 



1^ Bull. Acad. Sci. St. Petersburg, p. 185, 1909. 



PROC. AMER. PHIL. SOC, LIII,, 213, D, PRINTED JUNE l8, IQI/]. 



