Summer is the time for outdoor festivals, and there’s one for every interest—even obscure rock enthusiasts. (The mineral formations, not the music.)

The third annual "Puddingstones of Cheboygan County" festival is taking place this weekend—August 5 and 6—in downtown Cheboygan, Michigan. The gathering honors a rock you’ve probably never heard of, one that’s only found in a select set of places, one of which is northern Michigan.

Puddingstones are a type of Jasper conglomerate, consisting of many individual rocks within a larger one. They were formed amid the glacial drift in the Great Lakes region and contain Jasper quartz, Precambrian Canadian Shield rocks, sandstone, and other redeposited sand and pebbles.

The rocks earned their name from early British settlers who thought the rocks looked like boiled suet pudding with berries. There are actually several types of so-called "puddingstones," including Hertfordshire, Schunemunk, and Roxbury, the last of which is the state rock of Massachusetts.

At this weekend’s festival, stone and mineral exhibitors are displaying their goods, rock-related events are taking place, there's an Easter-egg style puddingstone hunt, live music, a suet pudding baking contest, and a puddingstone contest with categories like "most red in a stone" and "images seen in a stone."

Michiganders apparently really love their rocks: The state also holds a Petoskey Stone Festival every year to honor their own state stone.

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