MIARGYRITE SILVER ORE FROM CALIFORNIA — SHANNON 



SO striated as to give verj' poor signals. Even when the correct 

 orientation is known, this habit makes very precise adjustment on 

 the goniometer ahnost impossible. Moreover, most of the crystals 

 appear to have been fractured through the center, and the halves, 

 although firmly recemented, are displaced a degree or more with 

 reference to each other. 



The crystal illustrated in Figure 1 (crystal 1993) is from the speci- 

 men (Cat. No. 95334) of massive miargyrite which furnished the 

 material for analysis. It is typical of those occurring in the vugs 

 in massive ore, although the larger of these are deeply striated and 

 grooved and, being crowded and grown flat against the walls of the 

 cavity, are seldom completely developed. These are somewhat 

 simpler in habit and show a less number of fcrrms than those resting 

 upon quartz druses. This crystal gave the following measurements: 



Measurements of miargyrite crystal, Figure 1 



Form 



No. 



10 

 11 

 12 



Letter 



Symbol 



Gdt. Miller 







ooO 



-10 



+ 1 



+ 1 



+ 21 



+ 21 



+ 31 



+!• 



+ 41 



_41 

 33 



_41 

 33 



001 

 100 



Toi 

 111 

 111 



211 

 211 

 311 



922 

 411 



413 



413 



Quality description 



Fair 



Good 



Fair 



do .---. 



do 



Good 



P. blurred 



Good, dim 



do... 



V. dim, end of zone 



Poor, dim 



do 



Measured 



91 51 

 90 00 

 90 03 

 22 03 

 22 05 

 36 01 

 35 28 

 45 48 



59 12 

 50 57 



49 39 



50 48 



8 32 

 90 00 

 39 31 



71 43 



72 13 

 74 26 



73 53 

 77 07 



77 30 



78 32 



56 11 

 56 11 



Calculated 



90 00 

 90 00 

 90 00 

 21 18 

 21 18 

 36 03 

 36 03 

 46 49 



57 32 

 54 31 



50 03 



50 03 



8 37 



90 00 



39 43 



72 15 



72 15 



1 74 28 



74 28 



76 46 



79 33 

 78 43 



56 30 



56 30 



