Datolite from the Keweenaw is a collector’s stone found almost nowhere else in this form: dense porcelain-like nodules, white to salmon to deep red, coloured by the native copper trapped inside them, cut open and polished to show it. They come from the mine dumps of the old copper workings around Houghton, Calumet and Lake Linden. Most dumps are PRIVATE or corporate ground; several Copper Country museums and shops sell verified material, and some properties sell dump-picking permits.
Datolite (copper-included)
Other places on the map within a couple of hours.
