Sunstone: Compass of the Vikings?

courtesy RocEverDark

How did Vikings navigate on those cloudy days that are so common in the North Atlantic?  Not by compass -- they sailed before the magnetic compass was known outside of China.  According to legend they used sunstones to navigate when the sky was overcast.  These magical stones could reveal the location of the sun even when it was hidden by clouds.

In the Icelandic saga, Rauðúlfs þáttr, the narrator describes the magic of the “solar stone”.

The weather was thick and snowy as Sigurður had predicted. Then the king summoned Sigurður and Dagur (Rauðúlfur's sons) to him. The king made people look out and they could nowhere see a clear sky. Then he asked Sigurður to tell where the sun was at that time. He gave a clear assertion. Then the king made them fetch the solar stone and held it up and saw where light radiated from the stone and thus directly verified Sigurður’ s prediction.

Photocourtesy of ArnieEin

Iceland spar, a transparent form of calcite, is the leading candidate for the sunstone of the Vikings.  These crystals will split the polarized light of sunshine into two beams if correctly oriented with respect to the sun.

Now Iceland spar has been put to the test.  As reported in last week’s Economist, Guy Ropars of the University of Rennes (France) has shown that if the crystal is calibrated on a sunny day by marking on it the direction of the sun, it will always point to the sun when lined up to produce two clear beams.  All that is required is a small patch of blue sky.

If Iceland spar were found in Viking shipwrecks or burials, it would indeed be a strong candidate for the mythical sunstone.  But not.  So far the only supportive archeological evidence is a large calcite crystal from an Elizabethan shipwreck.  That crystal is too opaque to test as a sunstone, having been in the ocean for several hundred years, but the researchers suspect it is Iceland spar and are subjecting it to further study.

Iceland spar, also known as optical calcite, has healing properties as does pretty much every other crystal in the world.  It is helpful “for those in need of clarity, and those who are learning about Law of Attraction and manifestation ... can amplify intent, and can be programmed for a specific purpose.”

I include this because it is so bizarre, to the point of being comical.  But there are people who believe and buy, amazing.  I learned about crystal healing only recently, while looking for photos of “crossed twins” of the mineral staurolite described in a post by Sandatlas.  Staurolite crystals can be used to “ground an individual with a tendency to “float away” from the material world, or to be lost in abstract realms of mental ratiocination”.  Personally, I like being in that state and will avoid staurolite.