26 



BUTLER AND SCHALLER: BEAVERITE 



outline and show the emergence of the positive acute bisectrix. 

 They may easily be taken for uniaxial crystals, as the axial 

 angle is small but variable. 2E is usually about 32°. Basal 

 sections of some of the crystals are divided into six radial seg- 

 ments and the plane of the optic axis in each segment is normal 

 to the pseudo-hexagonal prism edge. 



The following analysis was made on fresh, light gray crystals 

 of hinsdalite. They were examined microscopically and found 

 to be very pure but showed a slight zonal growth. 



Analysis oj hinsdalite 

 W. T. Schaller, analyst 



PbO.. 



SrO.. 



Al 2 Oi. 



S0 3 ... 



P2O5.. 



H 2 0.. 



31.75 

 3.11 

 26.47 

 14.13 

 14.50 

 10.25 



1.93 or 2 



2.92 or 3 

 1.99 or 2 

 1.14 or 1 

 6.40 or 6 



CaO, MgO, Na 2 0, K 2 traces. Density = 3.64. 



Formula 2 (Pb, Sr) 0.3Al 2 O 3 .P 2 O 5 ,2SO 3 .6H 2 O. 



Hinsdalite is infusible but whitens on heating. It reacts for 

 aluminum when heated with cobalt nitrate, and readily yields a 

 button of metallic lead. The water is driven off only at a tem- 

 perature of from about 400° to 600° C. It is insoluble in acids. 

 From its chemical composition and crystallographical form it 

 is seen to be closely related to svanbergite and forms an addi- 

 tional member of the alunite-beudantite group. 



MINERALOGY. — Beaverite, a new mineral. B. S. Butler and 

 W. T. Schaller. Geological Survey. To appear in the 

 American Journal of Science. 



The new mineral beaverite, a hydrous sulphate of copper, lead, 

 and ferric iron, was found (by B. S. B.) in the Horn Silver mine 

 near Frisco, Beaver County, Utah. The mineralization occurs 

 along a fault that has thrown Tertiary lavas down against Cambro- 

 Ordovician limestone. The ore is mainly a replacement of the 

 volcanic rocks. 



The principal primary minerals of the deposit are galena, 



