Marco, are you sure you're not three people?
You consistently keep coming up with so much good stuff (and so fast) it makes my head spin!
This stone, called solarsteinn, was used by the pre-medieval Vikings for navigation (and as a prism):
![[Image: 220px-Silfurberg.jpg]](https://upload.wikimedia.org/wikipedia/commons/thumb/1/14/Silfurberg.jpg/220px-Silfurberg.jpg)
It's probably something along the same lines as "Iris" crystal.
There's an article about it on You are not allowed to view links. Register or Login to view. which mentions how this material was used to create the first polarizing prism.
Kircher and Marci were among the early scientists to study prisms.
You consistently keep coming up with so much good stuff (and so fast) it makes my head spin!
This stone, called solarsteinn, was used by the pre-medieval Vikings for navigation (and as a prism):
It's probably something along the same lines as "Iris" crystal.
There's an article about it on You are not allowed to view links. Register or Login to view. which mentions how this material was used to create the first polarizing prism.
Kircher and Marci were among the early scientists to study prisms.