Scientists believe a crystal found at the site of a 16th-century English shipwreck is a sunstone, the near-mythical navigation tool rumored to be used by Vikings at sea.

It is the stuff of myths and legends. A Viking sunstone found in the remains of a sunken ship offers clues to researchers as to how the renowned Norse sailors were so good at what they did.

Divers recently found a rhombohedral crystal in the wreckage of the Alderney, an Elizabethan ship that sank near the Channel Islands in 1592 on its way to France.

A research team at the University of Rennes has said the stone was discovered next to navigation dividers, suggesting it might have been used in conjunction with the ship's other navigational tools.

A chemical analysis confirmed the crystal's make up. The perceived sunstone is made from Icelandic Spar, or calcite crystal - the material believed to be the mineral of choice for the Nordic seafarers.

Scientists have claimed that sunstones would have been very handy navigational tools for the sailors.

The milky-white substance polarizes light and therefore can give the user an accurate location for the sun, even on cloudy days.

The Viking sunstone found in the wreckage would have been held up to the sky and when it was hit by the sunlight it would have been broken up into an "ordinary" and an "extraordinary" beam.

The sunstone user would then have rotated the crystal until the pair of beams lined up thus locating the sun's position and creating an accurate reference point.

It would have been especially useful to use a Viking sunstone during twilight hours when the sun is on the horizon and the stars cannot yet be seen.

Sunstones were said to have been used by the Vikings in the days before magnetic compasses.

This is the first alleged Viking sunstone found and never has one been uncovered at a Viking shipwreck site.

The news has created quite the buzz and many are wondering what other secrets of the past will soon be discovered. Perhaps the Viking sunstone will be able to lead scientists to the lost city of Atlantis next.