Petoskey Stones

Michigan’s number one most identifiable fossil/stone and also our official state stone since 1965 is the Petoskey Stone. These fossils belong to the Hexagonaria Percarinata group originally from 350 million years ago, they are bits of those coral heads and most identifiable ones can be immediately spotted only if wet or if you know what you are looking for, otherwise they appear to be limestone. They do primarily reside in Lake Michigan between Charloix and Petoskey. I had the best luck driving Lake Shore Dr between the two cities, On the drive they have several roadside beach stops. The 3rd one from Charoloix I had the best luck with since it seemed to be a less common location for anything but boat launch. Try avoiding the big bleached piles of rocks outside of the water since those are the most commonly dug through. I went out further in the water because a lot of the pads of plants out there were protecting some of the stones and you can walk pretty far out without going above your ankles. I actually find more Petoskey stones outside of Petoskey since that’s where everyone goes to retrieve them and the natives farm them to sell. While out there you may spot a stone that is pretty similar to Petosky known as honeycomb fossils/ Charloix stones. They will have pitted holes in the stone also, but the key identifier is that the Petoskey will almost represent a hexagon outline with little lines almost representing a flower. Honeycomb fossils are a slight relative also to Favosite fossils (But do not have the distinctive tail following the holes that the favosites have) It is not advised to put these guys into a tumbler since they could get damaged with other stones and are older than most of the other stones you will find. If you make direct cuts into the fossil you will notice the pattern is throughout the stone and not just on the surface. I have noticed you can find Petoskey stones farther down the lake Michigan shoreline but if you cut through most of these they are only a pattern on the stone from being next to one of the fossils for a while. These stones if polished correctly can have a very high resell value inside the state and more so outside the state the farther from lake Michigan you are.

Picture: All are Petoskey Stone Specimens, How they were found. Shape of stone clearly varies. The Large Upper left yellow and black stone is a extremely weathered honeycomb fossil found on the Chicago side of Lake Michigan.

Michigan Septarian Nodules (Geodes) “Lightening Stones”

Lets start with the second most identifiable stone for Michigan: “Lightening Stones”. They are referred to this name by local ‘Michiganers’ and actually are variation of a Septarian Nodule. These Michigan Septarians were balls of clay that formed on the ocean floor somewhere around 50 million years ago, over time the balls of clay developed cracks that were later filled with yellow-White Calcite. They are considered what is known as a ‘Pseudo Fossil’. Occasionally you will find them with Crinoidea Fossils or with ‘Fossil Graveyard’ markings. I am unsure of the reason they refer them to Geodes, they do have a calcite filling but are not hollow on the inside and only go as deep as the original crack in the clay. I have attempted a different ways to polish these, it has taken awhile with trial and error. I have tried sanding down with different pieces of a drummel and even just trying to polish with a felt tip on a drummel. When they are under a drummel the clay starts to turn dark almost black and you will have the biggest clay dust storm. I have tumbled a few of these guys and they do come out very nice and smooth but they do turn a very dark brown, the calcite turns a little gray, and they do not shine, but the end result is they are usually smooth. I have also noticed that you can buy a very light craft finishing spray and if you take your time and make very light coats you can make them super shiny with a smooth outer appearance. With the polishing spray you have to be very careful, I have ruined quite a few from either coating one area too much and having half of it polished with less polished spots. Also make sure you are on a completely flat surface with no textures because it will imbed in the spray. I accidentally put the little nodules on a paper towel to dry, Lets just say they now have a nice floral paper towel impression! Ha! These special little guys are only found in the Allegan County Area of Michigan. They are said to be mainly found in South Haven ( I would suggest what is called ‘Deer Lick Creek’) Or in the Holland Area (Most people refer to ‘Pier Cove’). I have some photos of the current ones that I have: Picture One are some simple pendants made from a few tiny ones. Picture two contains the ones I found on my last trip only after hours. Picture 3 has a box of ones I have found in the past month. Picture 4 is just a fun example of how I present them to sell. Picture 4 is one of the largest ones I have found. They are primarily a little less the size of your palm, but on occasion you can find ones that large or even as tiny to make some pendants or charms.

Starting an additional resource

My rock hounding and Fossil Gathering began when I was 7 years old til about 15, after the divorce of my parents, when my father had us for a good portion of the summer he would drag us 10 hours up north in Michigan to spend 2 weeks near copper harbor. It was a huge drag as a kid because of the heat and no TV. My father would take us all over the Keewanaw stopping first to purchase a mine map from the same rock shop each year for 2$. From there we would spend from the break of dawn to the sun setting going through mine pits trying to find copper as well as a few other precious minerals. Now that I am older I have grown to appreciate these trips more and have recently sparked my interested in complete rock-hounding outside of gathering fossils wherever I go. Since we have snow every month but Late April Through Early September I utilize those months to collect as many minerals and fossils as i can and use the majority of the winter months tumbling/polishing/identifying. I have found their are not very many resources for beach stones/fossils for Lake Michigan and Lake Superior. I Have downloaded every guide, have bought every specific region for mineral books, and have tried to use my internet skills to get answers, even from some other blogging sites. Most of what I find is that they will post or document pictures of minerals/crystals in their top of the line polished pristine value, which is nice but if your looking for those minerals it is NOT going to look like that outside. Besides the polished specimens they have beach worn specimens that are either top notch or very limited. I have also come across most sources on the internet, the rock hounders do not know what the specimen is. I want to help out and post my findings both beach worn/dry, beach worn wet, polished and tumbled specimens to help other amateur rock hounders locate the ‘diamonds in the rough’. In no way am I ‘dogging’ on the rock hounders out there but there is a group of rock hounders that is primarily only looking for rough specimens in their area or folks who just want to know what they found on their beach this morning.