Thomsonite can be found locally on the beaches between Tofte and Grand Marais, on the Cook-Lake County line, on Isle Royal, Michigan and near Saxon Falls and the Montreal River Gorge on the Keweenaw Peninsula in Michigan. The color and texture of Minnesota’s Thomsonite makes it unique as gem-quality stones are found only in a limited area of Lake Superior’s shoreline about 5 ½ miles southwest of Grand Marais.

more informations are given atwww.thomsonite.com.