TRAVERSE CITY — Last September a Copemish man proved the days of finding giant Petoskey stones aren’t over when he pulled a 93-pounder from Lake Michigan waters near Northport.

But his happy find turned to disappointment when state officials confiscated his once-in-a-lifetime discovery. His prize now sits in a Michigan Department of Natural Resources evidence room. Lesson to rock hounds: Bigger isn’t always better, as taking the unusually large Petoskey stone violated Michigan law prohibiting individuals from removing more than 25 pounds of rock or minerals per year from state parks, recreation lands and Great Lakes bottomlands.

Scores of amateur collectors hit area beaches every spring and summer in search of the celebrated fossil with the status of state stone but few know the ins, outs and rules related to gathering these treasures. Local, state and federal laws applying to collecting rocks and fossils differ by city, county and township.

It's the user's responsibility to know the rules on public land, according to DNR regulation.

Gaylord-based First Lieutenant Vince Woods leads DNR and DEQ environmental investigations across the state. He was involved in the September Petoskey stone case. Collecting more than 25 pounds of the fossils places the find under commercial use, according to Woods.

“To avoid violating the rule, have an estimate of how much you want to collect and get a mining permit from the State Mineral Management office,” Woods said.

A long-standing federal rule makes Sleeping Bear Dunes National Lakeshore — and all national parks — off-limits to all rock collecting.

“It’s our mission to preserve the unimproved natural and cultural resources and values of the national park system for the enjoyment and education of future generations,” said Sleeping Bear Chief Park Ranger Phil Akers.

On the other side of the spectrum, Grand Traverse County has no rules prohibiting rock collection from county-owned properties. There are also no restrictions for rock collecting at Traverse City’s seven public beaches.

Bruce Mueller wrote the book on local Petoskey picking — “The Complete Guide to Petoskey Stones” — and co-authored the “Lake Michigan Rock Picker’s Guide.”

The retired high school and college geology teacher opened up his C&M Rock Shop in Beulah this April for its 50th season.

Mueller has hunted the popular Petoskey stone — which is actually fossilized coral — throughout northwest Michigan. Their distinctive honeycomb patterns are the remnants of individual coral cells, dating back 350 million years. Coral colonies thrived in the warm saltwater sea that long ago spanned Michigan, Mueller said.

“Petoskey stones were deposited at the top of the state — like a rainbow — from Petoskey to Alpena and as far south as Illinois,” Mueller said. “There are probably enough Petoskey stones buried in glacial drift in Michigan to form Mt. Everest."

Mueller, 85, knows the tricks for successful picks.

Color is a key identifier. The coral was originally white, but preserved in shale, they took on gray and brown tones from crude oil in their environment. Shape is another important clue, said Mueller. He suggests looking for smooth stones contoured like a bar of soap. The intricate pattern becomes visible only when the stone is wet. His tip is to keep a spray bottle of water handy when searching dry areas.

Season counts, too. Rock hunters know that spring conditions will push out a new crop of the prized fossils from Lake Michigan bottomlands to shorelines, Mueller said. Rocks held frozen in shallow waters during winter months wash onto beaches along with the spring ice break.

Some rock hounds wade into the water or scuba dive to collect the beauties. Mueller’s go-to Petoskey stone hunting spot is Peterson Park in Leelanau Township. In his younger days, his strategy was to walk south along the township park’s beach where few people ventured.

Other traditional hunting spots are Lake Michigan beaches along Old Mission and Leelanau peninsulas and shores north within Antrim, Charlevoix and Emmet counties. But don't limit the search to the lakeshore — Petoskey stones may be anywhere, and Mueller has noticed a tapering off of shore searches over the years.

“Petoskey stones are scarcer along the beaches than they used to be,” said Mueller. “But they can also be found in roads, in town — anywhere there is gravel.”

Climate change can also be a factor — studies conducted by NOAA’s Great Lakes Environmental Research Laboratory compared 20-year ice cover averages. Results show a downward trend in Lake Michigan’s annual icing.

But a winter of strong icing, like that of the 2015-16 season, could signal rock hounds that happy hunting is in store — within limits.

One of Mueller’s biggest personal finds was discovered near Bay Harbor south of Petoskey. It weighed an estimated 500 pounds. That giant doesn’t match the Petoskey stone found near The Homestead resort in 1999. A Sleeping Bear Dunes National Lakeshore visitor discovered the massive, roughly 2,000-pound Petoskey stone, measuring 40 inches wide and 20 inches deep. The stone is displayed at the park’s Pierce Stocking Drive No. 9 outlook point. It sits in plain view below the bulletin board, but few people recognize it as a Petoskey stone in its unpolished form, according to a park official.

More will be on display at the Petoskey Stone Festival in Antrim County’s village of Eastport. Grand Traverse Area Rock and Mineral Club co-sponsors the one-day event taking place May 28 at Barnes Park. Activities include a Petoskey stone hunt along the park beach, a children’s stone skipping contest, food, vendors and entertainment.

There you can find Petoskey stones without doing any looking.

“Folks get to see Petoskey stones in all shapes and sizes, polished and unpolished, mounted in jewelry, tables and cupboard hardware — in any possible use you can think of,” said club president Pierre LaFoille.

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