OPTICAL CALCITE
ICELANDIC SPAR
Composition: CaCO3
Viking Stone: Vikings used transparent calcite crystal -- also known as Iceland spar -- to fix the true bearing of the Sun, to within a single degree of accuracy.
This naturally occurring stone has the capacity to "depolarise" light, filtering and fracturing it along different axes..
 
How it works: If you put a dot on top of the crystal and look through it from below, two dots will appear. Then you rotate the crystal until the two points have exactly the same intensity or darkness. At that angle, the upward-facing surface indicates the direction of the Sun,
"A precision of a few degrees can be reached even under dark twilight conditions.... Vikings would have been able to determine with precision the direction of the hidden Sun.
 
Healing: Heals ailments of the throat and vocal cords. Aids in the understanding of 'double meanings' during communication and in clearing parts of the aura.