This is a decent example of the stone.
Swedish blue - this is a by-product of iron making in early 1800s.
It is slag from the melt. The material is glassy and shows flowlines.
Much of it is unusable because of the ash embedded in the material.
At one time, it was so common that it was used for fences and as
decoration on houses. Found today near Kiruna on the Norwegian
border, north of the Arctic circle.
If you go to my website - http://www.ganoksin.com/gnkurl/ep7z7w
you can see more material in the Scandinavian section.
There isn't much of it easily available. I first found it in Tucson
about 10 years ago.
At one time, I did a number of Scandinavian shows, in costume. The
Norwegians have many wonderful stones, the Danes have amber, and
this is what I found for the Swedes.