This sharp miniature is one of the prettier Bristol chalcocites in this size range I have seen, for the sharp aesthetics of distinctly twinned, upright crystals perched on such contrasting matrix. The crystallized calcite is uncommon, and really offsets the matte black chalcocite nicely. This specimen came from the Grace Dearborn collection to Phil Scalisi, 20 years ago or so. It is pristine except for a tiny ding, hard to spot, on the very tip of the cluster (an old ding, faded to same color as the rest, now). This detracts from value (or this would be $5000), but not from the overall display quality of the piece. Commercial mining began in 1837 and carried on until 1953 (according to Mindat.org) - this mine was a hugely important US resource through the Civil War years and beyond, and collectors lament its closing. Most regard the chalcocite from this mine as being the best on the planet, though English ones are pretty good too, I will say. Certainly, this is the most famous old locale in the US for the species.