Helgustaðir Mine

Helgustaðir is a disused mine on the shore of Eskifjörður where Iceland spar — a flawlessly clear calcite that splits a beam of light in two — was dug from the mid-seventeenth century into the twentieth. Crystals from this hillside were prized across Europe for microscopes and polarising instruments, and the largest, clearest specimen ever found came from here. Protected since the 1970s, it is now a quiet geosite: a short, steep scramble from the shore road reaches the openings, and with a torch you can step into the lower adit.