No sunstone, no Iceland 
Magnificent crystals of Iceland spar

Author: Tony Fogarassy, Vancouver, BC

Without the sunstone Vikings would not have settled Iceland, nor Greenland, Newfoundland. and Vinland. The rare optical properties of sunstone were the key to navigation in the north Atlantic. Sunstone, known also as Iceland spar, or by its mineral name, calcite, aided Viking navigators to locate the sun in fog and heavy overcast conditions sailing from Norway carrying precious supplies to settlements in Iceland.  Horses and sheep did not swim to Iceland on their own!

Viking ship captains kept their use of palm-sized sunstone crystals a closely guarded secret. They used the crystal’s unique property of the double refraction of light for navigational safety and to facilitate their highly successful shipping business. Vikings were determined to protect their monopoly on trade to, and ownership of, Iceland and other isles in the North Atlantic.  

While deposits of calcite were known in East Iceland, the best quality Iceland spar originated from the Helgustaðir quarry just east of the village of Eskifjörður, 60 km east of Egilsstaðir. The Helgustaðir quarry with its spectacular, optically pure calcite was known only to a handful of Viking settlers. Sunstones are teasingly mentioned in sagas – not surprising in light of the enormous commercial value of the mineral itself (pun intended).

Calcite is a very common mineral. But optically pure, rhombohedral sunstone crystals are relatively rare. Mexico, South Africa, and Crimea have sunstone deposits, but their optical quality is no match to the Iceland spar crystals of Helgustaðir. Indeed, the use of sunstones from Helgustaðir has been credited with the creation of numerous scientific instruments in physics, chemistry, mineralogy, and biology by researchers such as Michael Faraday (the relationship of magnetic fields and light) and Louis Pasteur (polarized light and organic compounds). 

Helgustaðir’s crystals weigh up to 250 kg and measure a metre across. Sadly, museums around the world plundered the Helgustaðir quarry in the 1800s. London and Vienna museums display samples of extraordinary quality and size. Iceland should repatriate these magnificent crystals and display them for Icelanders.

The government of Iceland has protected the Helgustaðir quarry as a natural monument. In recent years, Helgustaðir has been made tourist friendly with a fully plumbed restroom (pay-for-use via your cellphone on the honour system), excellent information signage about the quarry’s history, and a picnic table midway up the trail to the quarry site (an easy 1 km walk).

Please, please, please resist the urge to collect Iceland spar. It has been illegal to collect Helgustaðir Iceland spar for more than 50 years. It is a criminal offence to do so. As a geologist and a lawyer, I can assure you there is nothing more distressing than a “spar stealer” and “calcite crook.” Instead, take photos. Imagine the ingenious Viking use of the sunstone for passage across the North Atlantic to settle Iceland. No sunstone, no Iceland.