340 



BULLETIN 131, UNITED STATES NATIONAL MUSEUM 



of the habit illustrated in Figure 103. Upon measurement these 

 gave the following angles: 



Measurements of calamine crystal, Pittsburg-Idaho mine, Figure 103 



The prism zone is deeply striated and rounded by oscillation 

 between 6(010) and m(110). 



The specimen illustrated by Umpleby from this mine contains 

 numerous sheaves of the white bladed crystals resting upon smith- 

 sonite. These are flattened parallel to 6(010). Some of them are 

 unsymmetrically developed and then have a peculiarly monoclinic 

 aspect. On such is illustrated in the drawing, Figure 104. This gave 

 the following measurements: 



Measurements of calamine crystal, Pittsburg-Idaho mine, Figure 104 



Quality, description 



Fair, blurred. 



do 



Poor 



Fair, minute. 



Good 



Poor, dull 



Dull, n. s 



Good... 



Measured 



00 

 51 08 

 15 03 



89 50 



90 38 

 90 00 

 68 35 



90 00 



90 00 



90 00 



00 



31 42 



60 57 



(n. s.) 



52 49 



Calculated 



00 

 51 55 

 14 19 



90 00 



90 00 



90 00 



68 36 



90 00 



90 00 



90 00 



00 



31 22 



61 20 



50 39 



52 38 



In these crystals again the prismatic zone is strongly striated 

 vertically and the interfacial angles are rounded by oscillation. 



OWYHEE COUNTY 



A single specimen in the Museum collections (Cat. No. 65653, 

 U.S.N.M.) from the Laxley mine, South Mountain district, contains 

 calamine as drusy crusts of minute crystals and drusy surfaced 

 globular masses lining cavities in compact limonite. The calamine 

 crystals are normal in habit and tend to be aggregated into cockscomb 

 like forms or groups. 



