"This bead (attached images) turned up in an archaeological context in Bergen, Norway and is likely to be around 400 years old or more. As far as I know it is made of agate, probably from Idar-Oberstein. I spoke on the phone with someone at the local museum there, and apparently an expert who saw images of it was "90 % sure" the stone was sourced there.

Google searches turn up many similar beads with triangular facets and more uniformly coloured, though I am at a loss to find beads just like this one. I was hoping however to learn more. If you have knowledge to share about this type, I would be very interested."