new icn messageflickr-free-ic3d pan white
Iolite, both yellow and blue directions. | by albategnius
Back to album

Iolite, both yellow and blue directions.

Also known as Cordierite, this mineral is dichroic, exhibiting strong pleochroism. Called Vikings' Compass for its ability to detect the direction of solar polarization on an overcast sky. All photos in this set are of the same specimen.

692 views
0 faves
0 comments
Taken on October 23, 2010