Rockhounding along the shoreline of Lake Superior

Posted on June 15th, 2021

Michigan is an amazing place for rockhounding. In addition to the varieties of rock native to the area the glaciers brought with them rocks from more northern areas. The result is shorelines filled with a wide variety of beautiful stones. Collecting these stones is a very personal experience and there is a lot of variability in what people find appealing to collect. These are some of the clear favorites to look for in the Upper Peninsula.

  • Greenstones are Michigan’s State Gemstone and can be found in the Keweenaw Peninsula and along the shores of Isle Royale. These unique and beautiful stones are usually light to dark green and have a turtleback pattern.
  • Agates are the well known favorites for rock hunters along the Lake Superior shoreline. Lake Superior agates are about a billion years old and can contain a variety of colors including, white, red, gray, black and yellow. Broken smoothed sections are easily recognizable however unpolished agates can be difficult to distinguish from other stones.
  • Sodalite-rich syenite rocks have gained much attention recently due to its fluorescence under ultraviolet light. Gem and mineral dealer Erik Rintamaki gave the name “Yooperlite®” to this fascinating stone. To look for this stone you will need to go out at night and use a 365nm UV f It is difficult at best to find these stones in the daylight.
  • Pudding Stones are conglomerates which were brought from Canada to Michigan by glaciation. They are composed of a variety of smaller stones including quartz, red jasper, and black chert. The name comes from the resemblance to a Christmas pudding. Pudding Stones are frequently found.
Rocks by Karen Farrell Photography

Several man-made materials are also popular to search for along the shoreline:

  • Slag is a by-product and artifact of the late 1800s iron industry which was dumped into the lake. Though it is pollution it is quite popular to collect as it is a rather beautiful looking glass. Near Christmas is a good location to look for slag.
  • Beach glass is broken shards of glass that have been smoothed due to years of tumbling and rubbing against rocks and sand in freshwater. There are a wide range of colors but the most common are white (clear glass), light blue and brown.
  • Ceramics which are similar to beach glass in the process of formation come from a variety of original objects including plates, cups and tile. Especially popular pieces to collect retain elements of their original decoration including patterns, images and text.

If you are looking for additional information about Michigan’s stones, want to purchase particular specimens or want to see what you might find, try stopping into one of our area rock and mineral shops.

  • BJ’s Lapidary and Collectibles: 31600 W Front St., Trout Lake, MI 49793
  • Gitche Gumee Landing Gift Shop: 202 Ontonagon St., Ontonagon, MI 49953
  • Keweenaw Gem and Gift, Inc.: 912 Razorback Dr., Houghton, MI 49931
  • Nature’s Picks: 600 E Cloverland Dr., Ironwood, MI 49938
  • Prospector’s Paradise: County Rd., Allouez, MI 49805

Important Note: While out rock hunting please keep in mind that it is illegal to remove stones from a National Shoreline, and that there are limits to the amount you can collect from State Parks (DNR).