THE MINERALS OF IDAHO 



12' 



BOISE COONTY 



In the various mining districts of Boise County pyrite is abundant, 

 not only in the gold-bearing veins but also in the altered wall rock 

 adjacent to the veins where it accompanies sericite. In the Quartz- 

 burg district, in the Mountain Chief mine, pyrite occurs in the richest 

 ores as large pale masses consisting of imperfect cubic crystals up to 

 3 cm. in diameter with bismuthinite in quartz sometimes intergrown 

 with sphalerite, arsenopyrite, and chalcopyrite in masses of auriferous 

 sulphides, or as small brilliant cubic crystals disseminated in the 

 sericitized wall rock adjacent to the veins. In ore from the Native 

 Missourian mine auriferous pyrite occurs with sphalerite as small 

 disseminated grains in quartz. At the Carroll-Driscoll property 

 pyrite is intergrown with other auriferous sulphides in quartz in the 

 ore and also as large masses embedded in sericite gouge, the latter 

 often showing pyritohedral crystals up to 1.5 cm. in diameter. This 

 is the best crystallized pyrite thus far examined from the State. 

 Some of the crystals are rather highly modified. A portion of one 

 of the more complex individuals was measured and is faithfully 

 reproduced in the drawing (fig. 9). This gave the angles recorded 

 in the table below. Several of the forms appear to be new but 

 require substantiation, so that no letters have been assigned them, 

 the faces in the drawing being merely numbered to agree with the 

 table. The crystallized pyrite from this locality requires further 

 crystallographic study. 



Measurements of -pyrite from Carroll-Driscoll mine 



Form 



No. Letter 



Symbol 



Miller Gdt. 



1 

 2 

 3 



4 

 5 

 6 



7 



8 



9 

 10 

 11 

 12 

 13 

 14 

 15 

 16 



17 |\ 



18 / 

 19 

 20 

 L'l 

 22 

 23 D. 

 24 

 25 

 26 

 27 

 28 

 29 

 30 



001 

 010 

 014 

 041 

 027 

 072 

 012 

 021 

 120 

 032 

 043 

 034 

 340 



0.11.9 

 670 

 011 

 112 

 121 

 111 

 122 

 233 

 148 

 236 

 234 

 243 

 231 

 6. 10. 15 



2. 7. 10 

 128 



4. 5. 20 







OH 



04 

 0- 

 0- 



m 



02 

 «2 

 0- 

 0- 

 0H, 



CO — 



0- 



12 



1 



J4i 



-1 



-X 



Quality, description 



Measured 



Very good 



do„ 



Excellent 



Good 



Poor, oscillated 



Poor, blurred ._ 



Excellent 



Blurred.. 



Good... 



Medium 



Excellent 



do 



Very good 



Medium... 



Very poor, striated . 



Good 



Excellent 



Medium, striated.. 



Excellent 



. ...do_. 



Very poor, dim 



Very poor, nosig 



Medium 



Poor .._ 



Poor, striated 



Very poor 



Medium 



Very poor 



do 



Medium 



00 



00 



00 



00 



00 



00 



00 



26 66 



00 



00 



00 



36 51 



00 



40 13 



00 



44 43 



26 06 



44 40 



26 06 



31 31 

 15 50 



32 11 

 32 26 



26 06 



31 56 



32 07 

 15 50 



27 37 

 40 08 



00 



90 00 



14 04 

 76 26 



15 24 

 73 40 



26 39 

 62 46 

 90 00 

 56 25 



53 00 

 37 00 

 90 00 

 50 16 

 90 00 

 44 55 



35 08 

 05 51 



54 37 

 48 04 

 52 13 



27 10 

 30 45 

 42 41 

 58 58 

 71 33 

 37 26 



36 30 

 15 34 

 18 19 



Calculated 



00 



00 



00 



00 



00 



00 



00 



26 34 



00 



00 



00 



36 52 



00 



40 36 



00 



45 00 



26 34 



45 00 



26 34 



33 41 



14 02 

 33 41 

 33 41 

 26 34 

 33 41 

 30 58 



15 57 

 26 34 

 38 40 



00 



90 00 



14 02 



75 58 



26 34 



63 26 



90 00 



56 18 



53 08 

 36 52 

 90 00 

 50 42 

 90 00 

 45 00 

 35 16 

 65 54 



54 44 

 48 11 



31 00 



42 02 



56 08 



74 30 



37 52 



36 03 



15 37 



1 Indicates probable but unsubstantiated new form. 



