A team of archaeologists think that they may have found the first Viking sunstone. Two years ago we posted about Viking sunstones, the legendary, and indeed considered by many to be mythical, devices which allowed Viking navigators to locate the position of the sun even on heavily overcast or cloudy days. See our previous post - Did Vikings Navigate with ‘Sunstones’? Researchers had theorized that the sunstones were polarizing crystals that allowed Viking navigators to pinpoint the sun’s location based on variation in the polarized light as seen through the crystal. They had tested the theory with a polarimeter, a device that measures polarization. Until recently, no one one had found an actual Viking sunstone to test the theory.
Now a team from the University of Rennes in France say they found a crystal which may be a sunstone in the wreck of a British ship sunk off the island of Alderney – in the English Channel in 1592. The crystal has been found to be Iceland spar – a form of calcite known for its property of diffracting light into two separate rays. Tests performed on a similar crystal showed the direction of the sun could be determined if the crystal was rotated to where the two beams converged.
Thanks to Irwin Bryan for contributing to the post.