THE MINERALS OF IDAHO 249 



The ore of the oxidized zone is normally a relatively soft aggregate of 

 massive cerusite, fragments of quartzite, and ocherous to compact 

 limonite, with or without manganese oxides. There is usually more 

 or less bindheimite mixed with the cerusite and rarely some azurite, 

 malachite, linarite, plattnerite, pyromorphite, or anglesite. Cavities 

 in the massive ore are lined with crystals of cerusite often of great 

 delicacy and beauty. The crystallized cerusite is exceedingly variable 

 in form and appearance. Single simple isolated crystals are rare, 

 the mineral tending to form complex twinned aggregates. The 

 carbonate ores are now largely exhausted and fine specimens of crystal- 

 lized cerusite are rare although they are occasionally found in some of 

 the newer mines or prospects or in lease workings in the old stopes of 

 the large mines. 



Certainly no other district in North America and probably none 

 in the world has exceeded this region in the production of fine speci- 

 mens of cerusite, both in quality and number, yet these are now 

 practically unobtainable. They have all been lost or destroyed and 

 practically none have found their way into the large collections or 

 museums of the country and their existence has not, heretofore, been 

 mentioned in the literature. In the days when carbonate ores were 

 being mined almost every miner had a private cabinet filled with 

 choice specimens in a corner of his home and many gorgeous crystalli- 

 zations were on view in cigar cases, in hotels, boarding houses, and 

 barrooms; and these could, in most cases, bo had for the asking. Of 

 late years, however, they have largely been lost to sight. 



The first lead-silver ores mined were the ones which contained the 

 greatest amount of carbonate and furnished the finest crystallized 

 cerusite — -in the years from 1882 to 1890. Such ores were still mined 

 commonly up to 1900 and in 1901 the Hercules ore body began pro- 

 ducing specimens of truly wonderful character. There was for sev- 

 eral years, at the mouth of the No. 3 Hercules tunnel, a grotto walled 

 up with logs and provided with shelves on all sides where specimens 

 of crystallized cerusite, native silver, and pyromorphite weighing 

 from 10 to 200 pounds each were placed and exhibited to visitors by 

 candlelight. When this receptacle became crowded, and specimens 

 were constantly being added, a quantity would be cleared out and 

 thrown in powder boxes in the head house for anyone who wanted 

 them to carry them away. The showier pieces, and the ones most 

 esteemed locally, were the pure columnar masses or brilliant long-fibrous 

 aggregates and the solid masses of reticulated plates. The latter are 

 honeycomb-like masses of thin plates flattened parallel to &(010) and 

 twinned on m(110) giving triangular intersections. Specimens show- 

 ing crusts of small articulate crystals on gangue which would be 

 highly acceptable to a mineralogist were hot highly regarded by the 

 miners. The Hercules mine continued to furnish good cerusites for 

 54347—201—17 



