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 ...

Agates are formed from silica solutions filling gas bubbles in lava rocks, creating bands of color. The best time to find agates in Michigan is after a storm. Popular Michigan agate hunting locations ...

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 ...