Legendary Viking sunstones may be real

Courtesy University of Pittsburgh.

"A Viking legend which tells of a glowing 'sunstone' that, when held up to the sky, disclosed the position of the Sun on a cloudy day may have some basis in truth, scientists believe." The stone may actually have been an Iceland spar, a calcite crystal that could be used to pinpoint the Sun's location on cloudy or foggy days "within a degree." Read the full article at the Daily Telegraph.