Penfield and Frenzel — Identity of Cfialcostibite, etc. 33 



The measurements obtained by him will be found in column 

 YJI in the tables on page 35. 



Summary of the crystallographic investigations. — The fol- 

 lowing table includes all the forms which have been identified 



on chalcostibite, and their distribution is shown by the spherical 

 projection, fig. 4 : 



b, 010 



A 3 , 205 



/, on 



ft, 136 



r, 261 



c, 001 



e, 307 



s, 065 



r, 134 



a, 233 



I, 130 



j, 102 



t, 021 



v, 133 



ft 354 



A, 209 



h, 203 



w, 061 



7T, 265 



y, 474 



A,, 207 



d, 101 



q, 863 



/o, 263 



S, 475 



A 2 , 103 



i, 302 



g, 201 



p, 6.12.7 



<r, 4.12.5 



€, 476 



All investigators call attention to the striated character of 

 the crystals in the direction of the crystallographic axis b, and, 

 owing to the difficulty of always obtaining reliable measure- 

 ments, there may be uncertainty in the identification of some 

 of the forms in the zone 100 : 001. The only forms which 

 have been identified as prominent ones in this zone are A, d, 

 and g. The prominent development of the pyramids^? and q 

 with such complicated indices as 6*1 2*7 and 863, respectively, 

 on crystals from both Wolfsberg and Huanchaca, is certainly 

 very unusual, and there seems to be nothing gained by giving 

 to one of these forms simpler indices, since that would add 

 very much to the complexity of the remaining forms. 



Am. Jour. Sol— Fourth Series, Yol. IV, No. l.— July, 1897. 

 3 



