688 



walker: hopeite 



From crystal No. 1 the polar elements were found to be 

 p = 0.8277; q = 0.4720, corresponding to the axial ratios 

 a : b : c : : 0.5703 : 1 : 0.4720. These ratios are slightly lower 

 than those obtained by previous observers, though they are 

 very near the values of Levy — a : b : c : : 0.5723 : 1 : 0.4718. 



The details of the measurements given in the following table 

 were obtained from crystals 1 and 2 except the values for the 

 form (103), which are from the third. 



The principal faces are shown in figure 1, while all the forms 

 observed appear on the gnomonic projection in figure 2. 



Hopeite has been found in the zinc mines near Aix-la-Chapelle 

 and at the Broken Hill mine in Rhodesia. The occurrence at 

 the H. B. mine near Salmo, B. C, is the first recorded for the 

 American continent. 



