As of 10 pm last night, I can not only document dupioni was used by Vikings but the amount of metal thread work is AMAZING! The museum catalog states it's "gold-embroidered silk" but I'm more inclined to think at this time the metalwork is woven.
This was my second "find" within the past week.The first one is from Germany and has a rather large "fragment" in dupioni-as well as a completely intact reliquary bag.
The slubs on the Viking piece and the silk fragment are highly visible and don't even require a magnifying glass to see them.
For a sneak preview of the German find, please check out one my latest article on the Middle Kingdom Textile Artisan Guild of Withie and Woolmongers, http://www.mktag.org/. High relief metalwork embroidery. I plan on doing an article on both finds but at this time I can't figure out how to share the color picture of the Viking find due to copyright issues