The elusive Lake Superior agate. Rockhounds scour Lake Superior’s shoreline for these rare banded beauties—from the western reaches of the Keweenaw Peninsula to the U.P.’s easternmost Whitefish Point.

From the Leland Blue, a stone-like slag leftover from the iron ore and mining industry, to the glowing Yooperlite and Lake Superior agates found in the Upper Peninsula, Michigan is home to plenty of ...