Iceland Spar, or Optical Calcite, is said to have been used by Vikings for navigation on cloudy days due to its polarizing effects on light, technically called birefringence. Natural clarity, color, tone and patterns will vary.
The orange hue in these specimens is likely due to the presence of manganese. Each specimen is approximately 3.5-4 x 3-3.5 x 1.5-2 inches.
