Rock Discoveries

Unearthing the Hidden History of The Petoskey Stone

The Petoskey Stone: History, Characteristics, and Locations

Have you ever heard of the Petoskey Stone? It may sound like a precious gem to some people, but to northern Michigan residents, it’s a prized find that can be discovered along the shores of lakes, beaches, or in inland locations.

This stone has a unique past that dates back millions of years and is a treasure trove for those who love fossils and geological history. Let’s learn more about the origins, formation, and characteristics of the Petoskey Stone!

Origins and Formation of the Petoskey Stone

The Petoskey Stone is a fossilized rugose coral, known scientifically as Hexagonaria percarinata. Rugose coral was once abundant in the shallow seas that covered Michigan and the Great Lakes region over 350 million years ago.

The Hexagonaria percarinata was a six-sided coral colony dweller composed of individual polyps. Imagine a tentacle-like creature with a mouth in the center and an eye to detect predators in the water.

As the coral colony grew, it left behind a structure that was filled with mud, silt grains, and the remains of plankton. Over time, the coral structures accumulated and became bedrock that formed ancient reefs.

This bedrock was then covered by glaciers, and as the glaciers moved across the landscape, they smoothed the surface of the ancient reef. The Petoskey Stone is the remnant of these ancient reefs, smoothed by glaciers, and exposed again by erosion.

The Petoskey Stone is composed of calcite and silica that replaced the organic parts of the coral and became fossilized. The calcite and silica replaced the coral’s texture and original structure, creating the unique honeycomb-like pattern that has become so well-known today.

It’s fascinating to know that the Petoskey Stone is not only found in northwestern Michigan, but also southeastern Ontario, Canada, including parts of Michigan, New York, and Indiana, as well as Ireland, England, and Germany.

Naming after Petoskey

The town of Petoskey, Michigan, which is located on the shore of Lake Michigan, lent its name to the Petoskey Stone. But what is the origin of the town’s name?

It was named after an Ottawa Chief, Petosegay, who lived in the area and whose name means “rising sun.” According to local lore, Petosegay’s daughter married a French nobleman, who named the town after her. Alternatively, Petosegay had a daughter with a French trader or soldier and his daughter was named after the rising sun, which eventually gave the town its name.

Characteristics and Locations of the Petoskey Stone

The Petoskey Stone is a unique pebble-shaped stone that is rough on the outside and smooth on the inside. The stone’s unique pattern and texture make it easy to identify and recognize once you have seen it a few times.

The stone’s color can vary from light gray to deep brown, depending on the concentration of minerals found in the rock. The Petoskey Stone is primarily found along the shoreline of lakes, beaches, and the Little Traverse Bay area, with Petoskey State Park, Magnus City Park Beach, and Bay Front and Sunset Parks being some of the most prolific locations.

These stones are also abundant near the marina. While the Petoskey Stone is plentiful along the shoreline, it can also be discovered in inland locations, such as gravel pits, roadbeds, and river beds.

This stone has been found in places as far away as Iowa, Illinois, and Ohio.


The Petoskey Stone is a fascinating artifact of Michigan geology and history. It’s easy to see why it’s such a prized possession among those who find it, with its unique pattern and texture telling a story of the state’s ancient past.

Whether you’re searching along the shoreline of a lake or hard at work in a gravel pit, keep an eye out for the Petoskey Stone, and you may just discover a piece of history in your hands. Identifying and Collecting Petoskey Stones: A Guide

If you’re a rock collector or fossil enthusiast, finding and identifying a Petoskey Stone can be an exciting adventure.

The stone’s combination of unique appearance and geological history make it an intriguing addition to any collection. In this guide, we’ll explore how to identify Petoskey Stones, where to find them, and what to keep in mind when collecting.

Size and Appearance

Petoskey Stones come in a range of sizes, from small pebbles to larger rocks. The stones are known for their distinctive six-sided corallites, which are the individual polyps’ exoskeletons.

These corallites have a dark eye in the center and are arranged in a hexagonal pattern, giving the stone its unique honeycomb-like appearance. Petoskey Stones typically range in color from light tan to dark brown or gray and have a mottled pattern of light and dark hexagons.

Identifying a Petoskey Stone can take some practice, as the pattern may be less distinct in some stones than others. However, once you’ve seen a few examples, you’ll quickly become familiar with the stone’s unique appearance.

Finding and Collecting

Petoskey Stones are found along the shoreline of lakes, beaches, and riverbeds. In winter, ice sheets may expose new rocks and increase the chances of finding a Petoskey Stone.

However, it’s important to note that collecting Petoskey Stones is prohibited in some areas. Michigan law states that rock collectors are allowed to take up to 25 pounds from state and federal lands as long as they follow the collection regulations.

When searching for Petoskey Stones, it’s best to look along the water’s edge. The stones can be hidden among other rocks and may be more easily spotted when wet.

When you find a potential Petoskey Stone, it’s important not to pick it up right away. Instead, look first to see if it has the unique pattern of the stone you’re seeking.

If you’re unsure about whether it’s a Petoskey Stone or not, try wetting it to see if its pattern becomes more distinct. Once you’ve found a Petoskey Stone, you’ll likely want to clean and polish it to bring out the stone’s unique pattern.

Wetting the stone can help make the pattern more visible, but to truly bring out its beauty, you can use a polishing cloth or grit. Some collectors prefer to use a rock tumbler to polish their Petoskey Stones, which can create a smoother, more polished look.

It’s important to keep in mind that Petoskey Stones are not always easy to find. They are not as abundant as other rocks and minerals, and finding one may take some time.

However, the thrill of finding a rare pink Petoskey Stone, which is less common than the traditional light tan or gray stones, can make the search well worth the effort.

Limited Availability

Petoskey Stones are not a resource that can be endlessly harvested. The stone is a finite resource and is becoming more limited as collecting becomes more popular.

As a result, it’s important to practice responsible collection techniques and adhere to collection regulations to help preserve this unique geological treasure for generations to come.


Identifying and collecting Petoskey Stones can be a fun and rewarding experience for rock collectors and fossil enthusiasts. Knowing what to look for, where to find these unique stones, and how to collect them responsibly can help ensure that Petoskey Stones continue to be available to be enjoyed by generations to come.

So, pack your bags, head to the shoreline and explore the wonders of the Petoskey Stone. In conclusion, the Petoskey Stone is a fascinating fossilized rugose coral that tells a story of Michigan’s ancient history.

Its unique appearance and limited availability make it a prized possession for rock collectors and geological enthusiasts. By following responsible collection techniques and adhering to regulations, we can help preserve this treasure for future generations.


Q: What is a Petoskey Stone? A: A Petoskey Stone is a fossilized rugose coral found primarily along the shoreline of lakes in Michigan and other parts of North America and Europe.

Q: What does a Petoskey Stone look like? A: A Petoskey Stone has a distinctive six-sided corallite pattern with a dark eye in the center.

The stone is usually tan, gray, or brown with a mottled pattern. Q: Where can I find Petoskey Stones?

A: Petoskey Stones are primarily found along the shoreline of lakes, beaches, and riverbeds. They may also be found inland in places like gravel pits and roadbeds.

Q: Can I collect Petoskey Stones? A: Michigan law allows collectors to take up to 25 pounds of rocks from state and federal lands, but some areas may have restrictions or prohibitions on collecting.

Q: Is it legal to collect a Petoskey Stone? A: Collecting Petoskey Stones is allowed under specific guidelines and regulations, and the amount varies depending on the location you are in.

Q: How can I be sure I’ve found a Petoskey Stone? A: Petoskey Stones are distinguished by their unique pattern, which can sometimes be hard to identify without practice or when they are dry.

Wetting the stone surface can help make the pattern visible. Q: Is a Petoskey Stone always a polished shape?

A: Petoskey Stones are not always polished, though rock collectors can greatly enhance and highlight their pattern through polishing by using a polishing cloth or grit.

Q: Can I find different colors of Petoskey Stones?

A: Petoskey Stones come in various shades of colors ranging from light tan to dark brown or gray. Rare Petoskey Stones come in pink color too.

Q: Is it unethical to collect a Petoskey Stone? A: It is ethical to collect Petoskey Stones as long as it is under the specific regulations and guidelines, allowing for the preservation of these stones.

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