Helgustadir Mine

Helgustadir produced Iceland spar, a form of calcite so clear and optically pure that a crystal splits an image in two when you look through it, and from the seventeenth century onwards this mine was the main source in the world. The mineral mattered to science: it was used in polarising prisms and in optical instruments through the nineteenth century, and crystals from here sit in museum and university collections across Europe. Working stopped in the early twentieth century when the good material ran out. The site was protected in 1975 and collecting is prohibited - what remains is the open working, the spoil and the view down the fjord.

What you actually see

• The source of Iceland spar - the world's main supply for centuries.
• A mineral that split light - used in polarising prisms and optics.
• Worked out and closed - production ended in the early 1900s.
• Protected since 1975 - taking anything is prohibited.

When to go

June to September; the track is poor otherwise. Two hours.

Honest expectations

The good crystals are long gone to museums, so there is little to see in the rock itself. The walk up is short but steep and loose. Collecting is illegal here and enforced. No facilities.

Nearby

Eskifjordur is west; Reydarfjordur and route 1 are beyond.