Dec, 1908. 



MlNERALOGICAL NOTES 



149 



determination as <f> (S.0.10), although its position, so near that of the 

 unit dome common to linarite, would suggest the possibility of its 

 being confused with the latter. It may also be noted that the meas- 

 urement from a (100) a c (001), is nearly the same as from a (100) 

 a <f> (9.o.io). This would suggest twinning on the orthopinacoid, 

 but on careful study of the crystal no evidence of twinning could be 

 observed. The interpretation given above seems, therefore, to be 

 the most reasonable one. The pyramid / (£23) exhibits somewhat 

 rounded faces; the dome u (2oi) is also characterized by somewhat 

 undulating surfaces. No special characters were noted regarding 

 the other planes. The appearance of the crystal as a whole is shown 

 in Fig. 2, PI. L. In Fig. 3, PI. L a projection of these forms 

 upon the clinopinacoid is shown. This exhibits to good advantage 

 the characteristic zones of the crystal and its nearly square appearance 

 when seen in the direction of the ortho-axis. The following is a list 

 of the forms observed, together with some of the measured and cal- 

 culated angles. The new forms are marked with an asterisk. 



