THE MINERALS OF IDAHO 



215 



ADAMS COUNTY 



In the Seven Devils district calcite in massive or granular form is 

 common in the marble in which the ore deposits have been developed. 

 A large specimen of vein material from the White Monument mine 

 consists of large cleavage rhombohedrons of calcite, each of which 

 serves as a core to a spherical layer of radial-fibrous calcite. The 

 curved outer surface of these layers is drusy and formed by sharp 

 calcite rhombohedrons which in turn are coated over with a thin 

 layer of quartz crystals. The interspaces between the spheroidal 

 masses of calcite are filled with a mixture of dead-black melaconite 

 and green chrvsocolla with a small amount of malachite. 23 



BANNOCK COUNTY 



Very coarsely crystalline snow-white calcite occurs as the gangue 

 of chalcopyrite and galena in ore from the Fort Hall mine, Fort 

 Hall district. 



Crystals of calcite occur with hematite in cavities in garnet-calcite 

 rock from a locality on Lanes Creek, Bannock Count}^ in NW. }4, 

 sec. 9, T. 6 S., R. 43 E. 'These often show zoned layers of transparent 

 material and buff calcite colored by included iron oxide. The habit 

 of these crystals is shown in Figure 41 and the measurements made 

 on them are given in the following table: 



Measurements on calcite from Bannock County, Figure J+l 



Quality, description 



Measured 



Fair 



Very poor 

 .... do._.. 

 .... do.... 



do.... 



do.... 



30 00 



27 .. 



30 57 



30 00 



19 04 



13 30 



Calculated 



44 30 ' 30 00 



46 .. 



58 16 



64 23 

 58 23 



65 30 



30 00 



30 00 



30 00 



19 06 



13 54 



44 36 



44 36 



58 02 



63 07 

 56 26 



64 02 



The faces are dull with the characteristic appearance of calcite and 

 do not yield very exact measurements. The associated garnet and 

 hematite are described elsewhere. 



BLAINE COUNTY 



In Blaine County calcite is reported to occur in the ores of the 

 Hailey (Mineral Hill) district as cleavable masses and as combs of 

 scalenohedral crystals in the ores. 



" Charles Palaclie. Amer. Journ. Sci., vol. 8, p. 301, 1899. 



