Story and photos by Valerie Chandler.
With many beautiful beaches and stone quarries, Northern Michigan offers a great opportunity for a hobby such as rock collecting or perhaps the thrill of rock hunting. Kids tend to grow up playing with rocks here, whether skipping them on the water, using them in pretend play or stashing them in their pockets to add to their collections. Some of those kids grow up to be rockhounds, due either to a fascination with geology or the rocks’ eye appeal and collectability. Others make the discovery later in life. For me, as a child, it was the eye appeal and seeing my dad collect and polish Petoskey stones, which later grew into a more diverse collection of rocks and minerals.
Rocks
Thanks to Michigan’s geological history, our state is one of the best for rockhounding—especially along our extensive shorelines. Several varieties of stones and minerals can be found locally. One is the popular Petoskey stone, a fossilized Hexagonaria Percarinata; a Paleozoic-Era coral that thrived in reefs. It had hexagonal patterns all over its surface, and each hexagon was once a coral polyp; the dark center was the mouth, which used tentacles to nourish the coral. Similar to the Petoskey stone is a Charlevoix stone, which has a smaller hexagonal pattern.
Glacial movement downward from Canada caused sedimentary rock to form in river channels. A type found in Michigan is known as puddingstone. The stones are a conglomerate of primarily quartzite embedded with pieces of jasper, chert and other small pebbles. They have been found in Europe, Australia, India and even on Mars!
Lots of people hunt for beach glass, but if you comb the beaches from Frankfort to Leland, you might find the elusive Leland Blue stone. It’s a beautiful robin’s egg blue, but can vary from a greenish to purple-like color. The rock is human-made and a rarity, a byproduct of iron smelting phased out in the late 19th century.
Minerals
You can find minerals in our local counties, mostly in stone quarries, but they take some effort to dig up. Halite, a type of rock salt produced in quantities in Manistee, has been unearthed in our area. We are also home to pyrite or “fool’s gold,” named for its glistening gold appearance. In Michigan, but not necessarily locally, rockhounds can find fluorite, usually green or purple and transparent, but impurities can make it opaque. This mineral is comprised of fluorine and calcium. Glacial deposits also left us with gypsum, a typically yellow-hued sulfate. Often found in mines is a silvery black mineral, an iron oxide called hematite.
Upper Peninsula rockhounding
In the Upper Peninsula, you might discover raw copper in old mines, but most are not open to public exploration. Michigan’s state gemstone, chlorastrolite or greenstone, is rare and only found in the U. P., usually in the Keweenaw Peninsula, where collectors search waste rock piles from old copper mines. Greenstones are also spotted on Isle Royale, where collecting has been illegal since 2000. If you do find one, it is green to sometimes blue with a turtle shell-like pattern.
Along Lake Superior, you can search for highly sought-after agates washed ashore by waves. These beautifully banded rocks feature delicate layers of minerals in hues of red, orange, white and cream. They may not appear so beautiful in their raw form, but polished they are gorgeous and can sometimes appear transparent.
Relatively new in the rockhound world, Yooperlites were found in the Upper Peninsula, as one would guess, but they have been reported as far south as Chicago. Mostly comprised of syenite rock, similar to granite, they are rich with fluorescent sodalite which glows orange or yellow under ultraviolet light and often forms unique patterns in the rock.
Fossils
Michigan is also a haven for fossils such as crinoids, trilobites, brachiopods, favosites and halysites. Crinoid fossils look like small, stacked discs with holes in their centers; they are from stems of an animal that was a relative of a starfish, and the long stalk attached to the sea floor. Trilobites are segmented arthropods, which makes them easy to recognize. They are one of the earliest known groups, spanning more than 270 million years. Brachiopods have hard “valves” on the upper and lower surfaces and look like stone clam shells. Favosites, or honeycomb coral, are calcitic tubes packed closely together, resembling honeycomb or a lace patterns. Halysites, or chain coral, are tubes of coral that formed to look like links in a chain, fossilized in marine rocks.
To expand your collection to include rocks and minerals not found in Michigan, you can visit many online store or head to shops in Beulah, Frankfort and Traverse City.
When scouring our local shores and beaches, state parks or quarries, it’s important to know the law about collecting, since many have their own policies and regulations. Michigan law states an individual cannot remove more than 25 pounds of stones, minerals or fossils per year from state-owned land for personal or non-commercial hobby use. It is also illegal under federal law to remove stones from national lakeshores. Lastly, pay attention to where you look for your treasures and always ask for permission if you wish to enter private property. Happy hunting!
Valerie Chandler lives in Wellston with her husband Matthew and their border collie/Australian shepherd. She is a citizen and employee of the Little River Band of Ottawa Indians. The rocks, fossils and minerals pictured here are from her personal collection.
