202 Lindgren, Hamilton, Palache — Melanovanadite 



faint and often multiple signals. The figure reproduces 

 the habit of most of the crystals. 



Description of the forms : 



b (010) is always present, generally as a narrow, 

 bright face. The cleavage parallel to it is so perfect that 

 it is difficult to detach or even handle a crystal without de- 

 veloping cleavage surfaces. 



a (100) is represented on every crystal by a rather 

 broad curved surface which gives a train of reflections, 

 none of which is from a true face. 



c (001) is not present as a face. The inclination of 

 the clino-axis, to which it would be parallel, was calculated 

 from the other terminal faces present. 



h (230) forms narrow but distinct faces on every 

 crystal. Its faces are far more perfect than other forms 

 of the prism zone except b. 



(530*) is the dominant prism form; its faces are 

 broad but badly striated and their position-angles show 

 wide variations. 



Poor reflections were obtained from numerous other 

 prism faces but were too uncertain to be regarded as 

 indicating definite forms. None were found at all near 

 to the position of the unit prism which would naturally 

 be expected to occur rather than the two prisms with 

 rather complex indices given above. 



p (111) is the dominant terminal form. Its faces 

 are generally bright and often developed to such an ex- 

 tent as to reduce other terminal faces to mere lines. 



s (121) was observed but once as a minute face; it 

 has therefore been omitted from the figure. 



d (032) is always present and its faces have a better 

 quality than any others on the crystals. 



g (012) was present on each crystal measured but 

 with faces so small as scarcely to be measureabie. It 

 was- not figured therefore. 



w (101) is quite large on most crystals but its faces are 

 always curved so that the position-angles are widely 

 variable. 



The table contains the observed angles with their limits 

 of variation and the angles calculated from the derived 

 elements. 



