Evidence of Viking Sunstone

Lore suggested Vikings used special crystals to navigate under cloudy skies. The crystal of legend was locked in the verses of Norse myth with no evidence that it was real.

Now scientists believe that the 'Viking Sunstone' or 'Viking Compass' did exist. Though none have ever been found at Viking archaeological sites, a crystal was uncovered in a British shipwreck proving they existed.The crystal was found in the wreckage of the Alderney, an Elizabethan warship that sank near the Channel Islands in 1592. The stone was discovered near a pair of navigation dividers.

A chemical analysis confirmed that the stone was Icelandic Spar, or calcite crystal, the Vikings' mineral of choice for their sunstones, first mentioned in the 13th-century Viking saga of Saint Olaf. Today, the crystal would be useless for navigation, because it has been abraded by sand and clouded by magnesium salts. But in better days, such a stone would have bent light in a very helpful way.

The rhombohedral shape of calcite crystals refract or polarize in such a way as to create a double image. This means that if you looked at someone's face through a clear chunk of Icelandic spar, you would see two faces. If the crystal is turned to the right position, the double image becomes a single image. Then you know the crystal is pointing east to west. Authors say the crystal could be used to determine the sun's location with an accuracy of one degree, even when it was invisible to the naked eye. Sunstones helped Norse mariners navigate their way to Iceland and onwards to North America.