A nice sample of silver wires from the Porco Mine, in Bolivia.
The mines at Porco have operated since at least the late 1500's, and were among the the primary sources of Spain's silver for hundreds of years. The site was also known to the Incas, who took control of the area sometime between 1493 and 1527.
For all the ore that the Porco mines have produced over the centuries, remarkably few specimens exist from the mine. In fact, it seems that it is easier to obtain antique Spanish coinage minted from Bolivian silver than it is to obtain raw specimens, even though the mine operates to this day.