Rock Hunting Lake Huron
Lake Huron is not only one of the most beautiful of the Great Lakes, but it is also the second-largest of the Great Lakes. It’s officially connected to Lake Michigan to the west by the Straits of Mackinac. The Huron River, whose basin was carved by Pleistocene glaciers, flows southward to the St. Clair River and forms a large portion of the international boundary between Michigan and the Canadian province of Ontario.
Some of Lake Huron’s beaches are sandy beaches completely washed by waves, while others are cobble-strewn or cliff-edged. This variety makes Lake Huron an excellent location for rock hunting.
Lake Huron’s gravel beaches are world renowned for its Petoskey stones, making the region a must-see location for rockhounds. For additional variation, the Presque Isle region has been known to yield magnificent veined sandstone and even chalcedony geodes. The Rockport Recreation Area is a popular location for families interested in collecting Petoskey Stones and other fossils.
What kind of rocks can you find on Lake Huron?
These aggregates (which resemble Christmas pudding) were transported south from Thessalon, Canada, by glaciers. The stone is made up of spherical stones of red jasper, black chert, and white quartzite that have been “cemented together” by quartz. Pudding stones may be found on Drummond Island and along Michigan’s eastern coast. Near Clare, large pudding stone boulders have been discovered.
Lake Superior Agate
Lake Superior agates are beautifully banded rocks with delicate layers of iron-rich minerals. Stones are often seen with thin bands of reds, whites, oranges, and creams.
These agates from the northwest are produced by cooling lava eruptions. Because of the region’s high iron concentration, they have deep reds and burned oranges. The best place to look for them is along the beaches of Lake Superior, where the current transports them after cooling.
Petoskey stones have become a favorite find for rockhounds who have researched their unique properties and seek to add them to their personal collection. The stone is most often pebble-shaped and may be found in either a rough state inland or smooth state along shorelines of certain lakes.
Petosky stone is a fossil rock made up of the remnants of the rugose coral Hexagonaria percarinata. These corals are thought to have lived before the dinosaurs and flourished when the Great Lakes area was covered by a warm, shallow sea. A huge reef at the time supported a diverse range of marine life, including these six-sided coral colony inhabitants and the plankton they dined on.
Extinct halysite corals have tiny tubes that housed jelly-like coral creatures known as polyps. For defense, the coral polyps possessed stinging cells and also grabbed plankton food that went by in the ocean currents. As the corals developed, they formed walls of tube-like chambers known as theca, which proliferated and added additional links to the chain. They constructed enormous limestone reef structures on the seafloor as they multiplied. They flourished mostly during the Silurian era, which lasted up to 425 million years ago!
The Charlevoix stone at first glance looks a lot like its close reletive, the Petoskey stone, but generally are much smaller. The Charlevoix stone’s smaller corallites are generally lighter or white in color. The tiny corallites may appear empty or include some radiating lines which do not reach the center. Charlevoix specimens more frequently display a side view of long coral tubes with the fossilized coral polyp at the end. These polyps form the fossil’s well-known honeycomb pattern
Crinoid fossils resemble tiny cylinders with holes in the middle, similar to a tiny donut. They are made from the stalks of an animal that resembles a flower but is really a cousin of the starfish. The discs were piled to create a long stalk that connects the animal to the sea bottom. Because the Native Americans utilized their broken petrified pieces to create necklaces, another popular term for them is Indian Bead.
Favosites (Honeycomb Coral)
Favosites are an extinct coral type. The honeycomb patterns on their surfaces, where their coral polyps pushed out from their calcium carbonate substrate, are one method to identify them. They are most frequently found in the same areas as the Michigan Petoskey Stones and the Charlevoix Favosites Stones.
Granite is a light-colored igneous rock with big enough grains to be seen with the naked eye. It is mostly comprised of quartz and feldspar, with trace quantities of mica, amphiboles, and other minerals. Granite with this mineral composition often has a red, pink, gray, or white hue with black mineral grains visible throughout the rock.
Rugosa corals are so-called because they have a horn-shaped chamber with a wrinkled, or rugose, wall. Rugose corals were found on the sea bottom or on reefs. They have tentacles to assist them in catching prey.
Brachiopods are bottom dwelling bivalve that lived in ancient oceans. They’re considered living fossils as they are still present in todays oceans, although not nearly as prolific as they once were.
Can you find Petoskey stones in Lake Huron?
Hikers on certain Lake Huron beaches, as well as along the state’s Lake Michigan shore, may come across a geologic treasure: the Petoskey stone, which is actually the fossilized remains of colonial corals that existed 350 million years ago in the tropical seaways that sloshed over present-day Michigan during the Devonian Period. As a result, they are remnants of old reefs that have been flattened by currents over a long period of time. They were carried by continental glaciers from Alpena Limestone outcrops at Little Traverse Bay – the stone’s namesake town – to points beyond.
Is it illegal to take rocks from Lake Huron?
It is ultimately your responsibility to know the local rules and regulations regarding rockhounding, but what follows is what my understanding is of the law at the time of this writing:
Individuals are not permitted to take more than 25 pounds per year of any rock, mineral (except gold bearing material), or invertebrate fossil from state-owned property for personal or non-commercial hobby use, according to Michigan law. While the removal of stones from a National Lakeshore is prohibited by federal law.
Lake Huron Rockhounding Beaches
Lake Huron is lined with miles of beaches just primed for rockhounding. Petoskey stones, sea glass, horned coral, and crinoid stems abound on these shorelines, sometimes making it difficult to bring them all home. This is not a complete list by any means, but below are just some of the best rockhounding beaches on Lake Huron:
- Beaches in and around Lakeport
- The area North of Oscoda
- Beaches in and around Pointe Aux Barques
- Rockport Recreation Area. There is a quarry at this location that is worth checking out (Permission may be required).
- Beaches in and around Rogers City.
- Presque Isle gravel beaches and surrounding area