Fabled Sunstone Discovered In English Shipwreck

sunstone
A team of French archaeologists believe they have found a sunstone, a strange crystal that was said to help mariners locate the sun even on overcast days.

Some of the medieval Norse Sagas mention this device. In “Rauðúlfs þáttr,” King Olaf asks the hero Sigurður to point out the sun in the middle of a snowstorm. Sigurður points to where it is behind the gray sky. To test him, the king had a follower “fetch the sunstone and held it up and saw where light radiated from the stone and thus directly verified Sigurður’s prediction.”

One recent study suggests the “sunstone” was a double-refracting crystal, which allows light through when the light is polarized in certain directions. They brighten or darken depending on the polarization of the light behind it. Clouds block the sun’s visible light but let through a concentration of polarized light that can be detected by the crystal as it’s moved around. Double-refracting crystals such as cordierite, tourmaline and calcite are common in Scandinavia.

Some scholars have expressed doubts about the sunstone’s existence because “Rauðúlfs þáttr” is a highly allegorical tale full of magical events.

Now it appears the tale may not be all that fantastic after all. Archaeologists from the University of Rennes have been studying finds from a British ship that sunk in 1592 near the island of Alderney in the English Channel. They found a rectangular block of Iceland spar calcite crystal, a type known for its double-refracting properties. The crystal was found next to a pair of dividers that may have been used for navigation.

The researchers suggest that their discovery shows the use of sunstones lasted well beyond the Viking era.

The team’s results appear in the latest issue of the “Proceedings of the Royal Society.”

[Photo courtesy Alderney Society Museum]

The Viking Ship Museum In Denmark

Viking, Viking ship, Denmark
The Vikings were the greatest sailors of their age. They built sturdy vessels that took them as far as Greenland and even North America. A few of these amazing craft have survived to the modern day.

The Viking Ship Museum in Roskilde, Denmark, has five such ships on display. Fifty years ago they were discovered at the bottom of Roskilde Fjord, where they had been deliberately sunk to create a defensive barrier in the 11th century A.D. Silt and cold temperatures kept them remarkably well preserved and archaeologists were able to restore and display them.

Walking through the main hall of the Viking Ship Museum, it’s easy to imagine you’re in a busy Viking port. The ships are of various types, such as the knarr, a broad ocean-going trading ship. These were the ships that the Vikings took on their long voyages of commerce and exploration. The famous longship was for battle only and didn’t do well on the high seas.

There’s a longship here too, a 98-foot-long beauty that was probably the warship of a chieftain. Tree-ring analysis of the timber shows it was built in or around Dublin about the year 1042. The Vikings settled in Ireland in 800 A.D. and founded several towns, Dublin being the most important.

%Gallery-174000%There’s also a smaller type of warship called a snekke. Shorter than the longship at only 57 feet, it was still a formidable vessel and remnants of the shield rack and carved decoration can be seen on the side.

The best-preserved boat is a byrding, coastal trading vessel built of Danish oak. There’s also a small boat that may have been used for fishing or whaling.

After examining the displays – very well done and with signs in English as well as Danish – walk outside to the museum harbor. Here you’ll find reconstructions of some of the ships you saw inside as well as historic vessels from later eras of Denmark’s seagoing history. At the boatyard, you can watch shipbuilders using traditional techniques. The star attraction is The Sea Stallion from Glendalough, a reconstruction of the museum’s longship. It’s seaworthy, and tests have shown it reaches an average speed of 2.5 knots and a top speed of 12 knots when under sail. There are even a few surprises, like kayaks from Greenland and Borneo.

Some ships are actually used and visitors can go on boat trips around the fjord.

If you’re heading north after your trip to Denmark, check out the excellent Viking ship museum in Oslo, Norway.

[Photo courtesy Wikimedia Commons]