Pathfinder: Legacy of Fire
This high mountain lake is named for both its still, reflective waters and for the old silver mines in the surrounding area, leaving several abandoned tunnels cut into the mountains around the tarn. The original excavations look dwarven, and were likely the work of miners from the Hammerfalls. The deeper portions of the mines might even still be viable, but few prospectors dare brave the hazards of the Brazen Peaks to investigate. The mine tunnels might reach into the depths of the Darklands, which would make sense given tales of stunted, shadowy figures spotted around the outskirts of the lake.