The Cash Mine is located near the small town of Gold Hill, Colorado, approximately 10 miles west of Boulder. It is a classic high-grade epithermal gold telluride deposit, with native gold associated with various telluride minerals including hessite, petzite, and sylvanite. While the Boulder County Telluride Belt produced substantial gold, silver and tellurium over a 100+ year period, mining has largely been dormant there in the past ~75 years.
These specimens are from a collection of ore samples mined in the ~WWII to 1950's and are as rich as anything produced historically from the mine. They contain gold in characteristic thin veinlets, associated with hessite, petzite, and minor sulfide minerals (chalcopyrite and pyrite primarily). Most have been polished on at least one face to better show the complex ore mineral paragenesis, and they are fantastic samples for both the ore geologist and mineral collector. This material is rarely seen on the market today and we are happy to be able to offer some nice specimens here.
High-grade gold telluride vein exposed underground in the Cash Mine (photo copyright Colorado Geological Survey)
Portal of the Cash Mine (photo copyright Brendan Harrington)