Demystifying U.P. Thomsonite: what is it? where is it found? how does it differ from “true thomsonite”?
Used in Beth’s new dreamscape series as well as gemstone rings, U.P. Thomsonite has brought some unique color into our store!
“U.P. Thomsonite” is the close cousin of true thomsonite which is only found along the north shore of Lake Superior. U.P. thomsonite features very similar eye patterns and color bands to it’s cousin from the north. Dark eyelets with feathery inclusions create unique patterns commonly sought out for use in jewelry.
U.P. Thomsonite features dark green eyes and variations of pink that are often pastel colors; rarely found in true thomsonite. The pink and green colors in U.P. Thomsonite is actually internal reflections from copper inclusions (additional minerals trapped within the gemstone).
U.P. Thomsonite is formed in a similar process as agates, trapped air pockets within volcanic basalt fill with prehnite (mineral base of U.P. Thomsonite) and microscopic bits of copper. Prehnite is usually pale green in color (Left picture below), but the copper rich area of Lake Superior has created Pink Prehnite (right picture below). The color intensity in the U.P. Thomsonite is due to the grain size of the copper inclusions within the gemstone.
U.P. Thomsonite is difficult to remove from the Balsalt matrix without breaking the gemstone, so most of the stones are from pebbles collected along the beaches. These stones were naturally removed from the basalt by being tumbled in Lake Superior.
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