A. H. Chester — Krennerite from Colorado. 



377 



calaverite from those of sylvanite, and as shown by Pentield 

 (1. a), the calaverite crystals he examined have many charac- 

 teristics in common with sylvanite. It hardly seems possible 

 that these krennerite crystals are identical with the calaverite 

 described by Hillebrand. 



Prof. Pen field's note on the crystallography of this mineral 

 is as follows : 



" The crystals of krennerite were not very favorable for 

 crystallographic study, as they were striated and gave generally 

 poor reflections of the signal. Two crystals having the habit 

 represented by the accompanying figure were measured, and 

 gave sufficiently accurate measurements for the identification 

 of the forms, which correspond to the prominent ones identi- 

 fied by vom Path* and Schrauf.f The forms are as follows : 



a, 100 I, 320 



h, 101 



u y 122 



5, 010 m, 110 



P, 201 





c, 001 n, 120 



e, 011 





The following measurements were 

 ade : 





Measured. 



Calculated. 



cia. 1, 100/^320 



32° 25' 



32° 5i' 



a/^m, 100/sllO 



43 30 



43 15 



fl A «, 100/^120 



61 55 



62 0J 



a^h, 100 /s 101 



61 22 



61 43 



a A p, 100^201 



42 55 



43 



e/s e, 011/sOll 



54 15 



53 32 



m a w, 122^122 



26 43 



26 55J 



< m: 



m 



The perfect basal cleavage is a prominent feature of the 

 mineral." 



Rutgers College, March 28th, 1898. 



* 1877., Zeitsch. Kryst., i, 614. 



f 1878, Ibid., ii, 235. 



