Through a convergence of the ancient mythology meets reality, scientists say they have discovered evidence of the Viking sunstone, the mythical navigational aid Viking mariners used to travel from northern Europe to North America.

Before the magnetic compass was introduced in the 13th century, Vikings were believed to have used a type of crystal known as a "sunstone" to locate the position of the sun which apparently they could do with this apparatus even on cloudy or foggy days. Now a new study published on the Proceedings of the Royal Society website reports scientists have discovered an example of the legendary crystal at the bottom of a British ship wreck that sunk off the island of Alderney in 1592, according to the BBC. The crystal or Viking "Sunstone" was originally found 30 years ago.

The team from the University of Rennes in France say they found the crystal 30 years ago while investigating the wreck. The crystal or Viking "sunstone" was Iceland spar, a type of calcite that diffracts light into two rays. When you rotate the crystal, the point where the two beams converge indicates the direction of the sun.

"We demonstrate that Alderney-like crystals could really have been used as an accurate optical sun compass as an aid to ancient navigation, when the Sun was hidden by clouds or below the horizon," the study said.

The study's authors said their findings may help identify other crystals used by the Vikings.

"The evolution of the Alderney crystal lends hope for identifying other calcite crystals in Viking shipwrecks, burials or settlements."