The newest famous stone in America: in 2017 a local rockhound, Erik Rintamaki, worked out that ordinary-looking beach cobbles on the Lake Superior shore blaze orange under 365-nanometre ultraviolet, because they carry fluorescent sodalite. Geologists confirmed and described them the following year. Walk the shore after dark near Grand Marais with a proper UV torch and the beach lights up like coals. PUBLIC shoreline in places, but check land status, and bring a real 365nm lamp, not a cheap 395nm one.
Fluorescent sodalite syenite
See it on the map
Other places on the map within a couple of hours.
