Icelandic spar was thought to be used for Norse sailors as a means of a telescope f sorts or more accurately a guide. Some more modern-day Norse kind used a piece as way in a ring as if to say they had found the treasure they had been searching for in their spouse.
Vikings may have navigated by looking through a type of crystal called Icelandic spar, a new study suggests. In some Icelandic sagas—embellished stories of Viking life—sailors relied on so-called sunstones to locate the sun's position and steer their ships on cloudy days. The stone would've worked by detecting a property of sunlight called polarization. Polarization is when light—which normally radiates randomly from its source—encounters something, such as a shiny surface or fog, that causes the rays to assume a particular orientation.