Kraus and Cook — Iodyrite from Tonopah. 



217 



lower poles. Especially Zepharovich, in reporting upon the 

 forms observed on artificial crystals with a decided hemimorphic 

 development, is not at all clear in his statements as to the occur- 

 rence of certain pyramidal forms. In the text these forms are 

 indicated as occurring only below, while in the table of angles 

 they are given as upper forms. It is also rather common for 

 crystallographers, when describing the forms on hemimorphic 

 crystals, to designate the upper and lower forms possessing the 

 same indices by different letters. This is somewhat clearer 

 but still confusing. 







Natural 



u 



Artificial 



Chile 



Dern- 

 bach 



Lake 



Valley 



Broken Hill 



Tonopah 



-4-3 

 -t-3 



<x> 



Zepharo- 

 vich 



Des Cloi- 

 zeaux 



Seligmann 



Genth 

 &Eath 



Spencer 



Kraus and Cook 



C 



{ 0001 J 



{0001} 



{0001} 



10001} 



{0001} 



{0001} 



{0001} 



{0001} 



c' 



. . 



{0001}* 



{0001} 



{0001} 



. . 



{0001} 



{0001} 



{0001} 



m 







{1010} 



1010 



{1010} 





{1010} 



{1010} 



{1010} 



a 



{1120} 























{1120} 







P 







{10.12} 



























r 



{1012} 



{1012}* 





























{1011} 











{10.11} 



{1011} 













o' 



{1011} 

















.. 





i 



{2021} 



{2021} 



{20211 



{2021} 



{2021} 



{2021 







{2021} 



i' 



{2021} 



{2021}* 



{2021} 



{2021} 





{2021 





{2021} 



V 



{2023} 



. _ _ . 













. 











f 









{3031} 











{3031} 









f 



. . _ . 







{3031} 



















. .. _ . 



g 











{3032} 











|3032} 









g\ 











{3032} 









t ' 



. 







e 



' {3034} 































u 



{4041} 



{4041} 





{4041} 











{4041 



.... 



v! 







{4041}* 

















{4041 







r 

 7T 



{4045} 



_ _ _ _ 















..-■- 









P 



{9.9.18.20} 



























r 





























{7074} 



t 





























{7073} 



X 





























{7071} 



y 































{9091} 



y' 











_ .. _ _ 



















{9091} 



10 































{9092} 



10 ' 







. _ . _ 







_ _ . . 















{9092} 



s' 



. . _ - 





















. 



{15.0.15.8} 



z 



























{33.0.33.2} 



* Inasmuch as Des Cloizeaux makes no definite statement as to the develop- 

 ment of these crystals, we have considered them as being apparently holohedral. 



