How the Vikings may have used calcite to locate the position of the Sun in a cloudy sky
The Sunstone: Secret of Viking Navigation
Experiments in Viking Navigation Viking Sun Stone
let a hick show you how to use a Viking stone compass
Viking Sunstone Accurate As A Magnetic Compass! | Expedition Unknown
Vikings (2013) History Channel Series - Navigate with a sunboard
Did the Vikings use the sunstone for navigation?
Viking Sunstone (e.g., Iceland Spar) Double Refraction, Not Direction of the Sun
Using Polarized Sunglasses as a Viking Sunstone
Perfect Conditions for Viking Sun Stone Use
Viking Sun Compass
Mythical Viking Sunstone Is Real
Viking sunstone (Iceland spar)
Viking Sun Stone in Action, Example 1.
Viking sun stone, CaCo3
Viking sunstone demo
Forgotten Adventuring Gear: VIKING SUNSTONE
The secrets of Viking navigation - An interview with a captain of a Viking ship replica
Viking Sunstones and Mummy Health Secrets
Iceland Spar: the Mineral That Changed Science