WATSON AND WHERRY: PYROLUSITE FROM VIRGINIA 



559 



place chiefly in the direction of the 6-axis, so that the greatest 

 shrinkage occurs along this axis.^* 



Figure 1 presents the average development of crystals of this 

 occurrence. Some crystals are even thinner than this, but on 



TABLE 2 

 Angles op Pyrolusite after Manganite from Powells Fort, Virginia 



a:b:c = 0.8612: 1:0.5629 



FORMS, 

 STUBOLS 



Q 493 



DEVELOPMENT 



Poor, irregular 



Narrow, dull 



Part of curve 



Part of curve 



Part of curve 



Flattest part of curve 



Part of curve 



Narrow but bright 



Narrow but bright 



Part of curve 



Part of curve 



Flat part of curve 



Part of curve 



Part of curve 



Flattest part of curve 



Part of curve 



One curved face, doubtful . 

 One curved face, doubtful. 

 May be represented by X 



and Z 



One curved face, obs. bj' 



Flink 



'^ It is also possible that this axial ratio belongs to pyrolusite itself, and that 

 the crystals are not pseudomorphs at all, as noted in Part I. 



