Mysterious Crystal Sunstones Could Help Explain The Vikings' Success


Tom Hale


Tom Hale

Senior Journalist

Tom is a writer in London with a Master's degree in Journalism whose editorial work covers anything from health and the environment to technology and archaeology.

Senior Journalist

How did Vikings become so efficient at sailing and navigation? Perhaps, the answer is sunstones. Catmando/Shutterstock

Seafaring Vikings stormed out of Scandinavia and discovered the new lands of Iceland, Greenland, and North America with no access to modern navigation instruments. So how did they become so effective at navigating the harsh northern seas? Without a doubt, they used the stars, the Moon, and geographical landmarks to coordinate, but what happens when the Sun isn't shining and you're sailing through Scandinavian clouds and fog? New research hints that their legendary seafaring skills could have been helped by the use of crystal sunstones.

Two researchers have recently been working with computer models to figure out just how effective these unusual crystals were at helping Vikings voyage from Norway to Greenland. The findings suggest that the sunstones are not just superstitious nonsense of days gone by – they might have been the secret weapon that secured the Vikings' navigational prowess.


These mysterious stones are talked about in many of the Sagas of Iceland, a collection of old stories about the events of 9th, 10th, and 11th century Iceland. According to these accounts, longboat sailors would hold these transparent crystals up to the sky against the thick Arctic fog and heavy cloud. Judging by how the light polarized and the shape of the beams, navigators could work out the direction of the Sun, even if it was obscured.

Some historians have thrown down on the sunstones because no physical examples have ever been unearthed. However, this new study highlights that the stones could have dramatically increased the chances of a Viking ship making it across the northern stretches of the Atlantic Ocean. It even hints that the stones could explain how the Vikings were so successful at seafaring and discovering new lands.

The sunstones hold important light polarizing properties. ARNIEIN/WIKIMEDIA COMMONS (CC BY-SA 3.0)

They simulated thousands of Viking ship voyages attempting to reach Greenland from Bergen in Norway with varying cloudiness at times of the summer solstice and spring equinox. Approximately 1,000 voyages is the number OF excursions that could have set sail to Greenland during the 300 years of the Viking era.

They discovered that Vikings could have made the journey with a 92 to 100 percent success rate if they used the sunstone every three hours. If they used the sunstone every four hours or more, this success rate would drop to just 32 to 58 percent. Using the stones even less would have meant the navigation success drops to as low as 1 to 6 percent, depending on the season.


“We showed that this navigation method can function well under cloudy skies on a voyage with varying cloudiness if the navigation periodicity is small enough and is distributed symmetrically before and after the time point of the real noon,” the study concludes. “Nobody knows whether the Vikings really used this method. However, if they did, they could navigate with it precisely.”

[H/T Science Magazine]


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