Vol. 5] Ealde. — Notes on Some California Minerals. 229 



lens, and it was only by the measurements that the writer could 



in most eases tell whether he had brochantite or caledonite set 



up. The hain't of the brochantite crystals is in general different 



from that of the caledonite. The crystals are characteristically 



in thin plates, tabular to (010) and elongated prismatic and in 



the direction of the a-axis. Occasional (010) is narrower with a 



corresponding- increase in the width of the prismatic faces, thus 



giving a more stocky appearance to the crystals. The general 



habit and common combination of forms is seen in plate 19, fig. 4. 



The forms occurring on the crystals are : • 



c (001) e (012) 



b (010) i (011) 



m (110) v (101; 



r (120) g (041) new 







Measured 



Call 



■ulated 











P 



4> 



P 



c 



001 



0°00' 



0°00' 



0°00' 



0°00' 



b 



010 



00 



90 00 



00 



90 00 



m 



110 



52 05 



90 00 



52 07 



90 00 



r 



120 



32 40 



90 00 



32 44 



90 00 



e 



012 



00 



13 37 



00 



13 47 



■i 



011 



00 



25 50 



00 



26 08 



g 



041 



00 



62 35 



00 



63 00 



V 



101 



90 00 



32 12 



90 00 



32 14 



The base was observed on one crystal only and as a mere line 

 face. One face of e is the common terminating form, yet on the 

 crystal having the base both faces occurred in one end. The 

 new form g occurred as a narrow face between b and e, but was 

 found only once. The prism m shows the best faces on the crys- 

 tals, and gave the best reflections. The remaining prism r is 

 also usually good, but sometimes rounds by striatures into b. 

 The crystals also showed a pyramid, and rough measurements 

 indicated that it was the unit pyramid (111), but no good reflec- 

 tions could be obtained from it. The pinacoid b is striated ver- 

 tically and presents one good face, giving a fair signal, while the 

 opposite side is rounded and striated, and gives only a train of 

 signals. There is some doubt regarding the system of crystal- 

 ization of brochantite. The crystals from this locality possess at 

 least two planes of symmetry, but the striking difference in the 

 development of the two braehy-pinacoidal sides suggest that they 

 may be hemimorphic-orthorhombic. 



