Water Sapphire

Water Sapphire or Iolite is the gemstone of the Vikings, The Viking mariners used thin pieces of it as the world’s first polarizing filter. Looking through an iolite lens, they were able to determine the exact position of the sun, and navigate their way safely to the New World and back.

The property that made iolite so valuable to the Vikings is its extreme pleochroism. Iolite has different colors in different directions in the crystal. A cube cut from iolite will look a more or less violet blue, almost like sapphire, from one side, clear as water from the other.