PEOCEEDINGS OF THE NATIONAL MUSEUM. 



VOL. 63. 



The agreement is satisfactory. However, in common with the 

 other prismatic forms here hsted as new, this form does not fit into 

 the rhytlimic series when its zone is analyzed according to Gold- 

 schmidt's Law of CompUcation. Extra or irrational forms are not 

 rare with this mineral. 



Fig. 2.-STEPHAOTTE Crystal 2 with Forms (225), (290), (3-10-0) and (1-15-0) Showing Actual 



Development. 



8.10.0 (ooijO). Observed only once as a broad line face yielding a 

 moderately good signal on crystal 2. Angles: 



Measured <^=25 09 p=90 00 



Calculated -^=25 30 p=90 00 



Difference <i>= « 21 p= 00 



