Most people do their rock hunting during the day, but you can't find "Yooperlites" until the sun goes down. Yooperlites are rocks that fluoresce in the dark under ultraviolet light. They became known ...

In a recent study, geologists say Michigan is home to the oldest known rock in the nation. Watersmeet gneiss is found in Michigan's Upper Peninsula. Minnesota's Morton gneiss previously held the title ...