NO. 2060. WOLFRAMITE, BERAUNITE, AND AXINITE— WHERRY. 507 



place in crystalline substances that adsorption does in colloids, and, 

 indeed, is probably the same effect. At least it is among the elements 

 the compounds of which show the greatest tendency to take on the 

 colloidal form that mix crystal formation is most frequent. 



Tungsten and columbium are ahke only in that both can act as 

 anions toward the more strongly electro-positive elements, and dif- 

 ferent in practically every other chemical property — in valence, 

 behavior with reagents, etc. — so that they can not be expected to 

 replace each other isomorphously. The most reasonable explanation 

 of the condition of the columbium and tantalum oxides in wolframite 

 is, then, that they are present as mix crystals, or, in other words, that 

 the several point systems have interpenetrated to such an extent that 

 they have become at least pseudohomogeneous.^ Wolframite is of 

 course not susceptible to optical examination, nor can any crystal 

 angle measurements be made on the present specimens, but if they 

 could be so studied effects such as those shown by other mix crystals 

 would no doubt be observed. Such intergrowth produces marked 

 effects on the crystal angles of the columbite group of minerals, 

 which, as will be more fully explained elsewhere, are probably to be 

 regarded as composed of mix crystals of a very few fundamental 

 compounds; the principal ones, the compositions of which are 

 R^CbjOg and R'TaaOg, are trimorphous, having isometric, tetragonal, 

 and orthbrhombic forms; so that, even admitting that the analyses 

 of members of this group are to some degree correct, the number of 

 ''species" into which it should be separated is greatly overestimated. 



In summary, two wolframites have been analyzed and their compo- 

 sitions discussed, a standard nomenclature for such isomorphous mix- 

 tures recommended, and the columbium and tantalum oxides found 

 shown to most probably exist in mix crystal form. 



A NEW OCCimilENCE OF BERAUNITE. 



The rare iron phosphate beraunite was discovered near Hellertown, 

 Northampton County, Pennsylvania, by the department of geology 

 of Lehigh University in 1911. The exact locality is the northeast 

 corner of an abandoned iron-ore pit, 1 mile southeast of the center 

 of the town. It was analyzed by Mr. J. S. Long, assistant in the 

 department of chemistry, and later more thoroughly studied by Mr. 

 Louis H. Koch, assistant m mineralogy, as part of the work for his 

 degree of master of science at Lehigh. Specimens were brought by 

 the writer to the United States National Museum (Cat. No. 87284), 

 and further investigated and the combined results of all the work 

 are here presented. 



iThe apparent excess of iron oxides, If not due to analytical errors, may be explained in the same way, 

 which would be favored by their similar crystallization: Prior, Mineralogical Magazine, vol. 13, 1903, p. 217. 



