Gold, Sylvanite, Calaverite

This is a specimen that we have often seen over the years, coming out of Cripple Creek, CO, in particular. The gold mines of Cripple Creek were rich in gold telluride minerals such as calaverite and sylvanite. The tellurides are not that exciting to look at, to non-mineral collector types. Prospectors, miners and collectors would often "roast" chunks of telluride bearing ore with a blow torch to cause the tellurium in the telluride minerals to be driven off as a gas. This would leave just gold (and/or silver) which would bubble out of the rock and solidify as golden bumps on the quartz fragment. Here is a good example of "roasted" ore, gold droplets bubbling out of the quartz and all!