A blacklight illuminates a “Yooperlite” rock — a new rock discovery made by a Michigan gem and mineral collector, Erik Rintamaki. Erik Rintamaki/Facebook/Yooperlites Erik Rintamaki was searching for rocks on a Michigan beach last summer when he made what he calls a “mind blowing” discovery. Resting among the thousands of pebbles covering the Lake Superior beach, Rintamaki saw a glowing...