My first Lake Superior Agate found on the beach at Black River Harbor
near Ironwood, Michigan. Unfortunately mistakes in tumbling
resulted in some fractures.
Part 2 - Recognizing Rocks & Agate Collected on Lake Superior Beaches (you are here)
The first two reference books for Lake Superior beach rocks and agates I found helpful are: Sparky Stensaas' "Rock Picker's Guide to Lake Superior's North Shore" and Susan Robinson's "Is this an Agate." Armed with Sparky's and/or Susan's book plus some of the pictures and descriptions I've provided here, perhaps will help you ID what you are collecting.
Another rock pickers reference book that helped me with agate hunting is "Understanding and Finding Agates " by Karen Brzys. It is now out of print but you may find it in some used bookstores. But Karen's new book "Agates Inside Out" is even more comprehensive. See my note on it below in the Agate Books section where we list several of our favorite references for finding Lake Superior Agates and identifying Superior beach rocks.
In addition to the reference books helping expand our agate hunting skill and knowledge, we were greatly helped by attending the "Rock On with Lake Superior Agates" festival. We learned a great deal more about identifying and collecting agates on Lake Superior's beaches. Lots of fun and great way to learn more about the hobby of beach rock and agate collecting.
This section continues with pictures and descriptions of some non-agate beach rocks plus provides a few pictures of agates we and others have found on Superior's beaches.
By the way, if you want to print out any of these larger images, just *right click* on the image and choose "copy image" to copy it to your hard drive. Once there you can click on it and print it out.
Minerals found in or as Lake Superior Beach Rocks
Quartz is a common mineral found among the beach stones, very hard (will scratch glass), somewhat translucent like frosted glass, and be white to yellow to grayish in color (impurities cause this variety in colors). Generally found as pebbles or imbedded in other rocks. In fact some of the pebbles were formerly amygdules that broke loose from the rock in which they were imbedded.
Calcite (calcium carbonate) at first glance may be thought to be quartz as it is a similar color (white to yellowish) and also commonly found, both as pebbles and imbedded within other rocks. But scratch it and you'll see it is much softer than quartz - chalky.
To the far right is an amalgam of quartz & calcite
Cherts are a tiny crystal form of quartz. Impurities make them less translucent than quartz. They have a waxy appearance, somewhat shiny. The rocks depicted in the picture are cherts. I think the stone on the left is a Jasper, a variety of chert.
Another variety of chert is Flint, essentially black chert. Note the waxy, somewhat shiny surface of this unpolished rock.
A few Lake Superior Agates
When I picked this guy off the beach at Black River Harbor, Michigan in 2008, I thought I had finally found my first Lake Superior Agate Beach Rock. It's bands are somewhat different than many of the Superior Agates I've seen. My wife Jo thinks it is a water-level agate. Here's two views of it.
In 2009 I found another Agate. This one is called a seam agate as the agate forms in a seam of the host rock.
Jeff King of Pickford, Michigan sent me some pics of 3 agates he found during the summer of 2009 on Lake Superior beaches near Munising, MI - - - Great finds Jeff, I'm jealous.
Now the attractive banded rock pictured here is NOT an agate. But could easily be mistaken for an agate due to its banding and chochoidal fracture pattern. But this rock is a banded chert, an agate cousin, but not an agate. The bands formed similar to how they form in a true agate but the crystal granules are so tight that the rock is opaque rather than translucent or partially translucent. Another marker that it is a chert rather than an agate is its color is atypical of a Lake Superior Agate.
Lake Superior Agates in Disguise
Here's an example (left) of gnarly rock you might pick up on the beach and through away, but if you look close and understand characteristics of Lake Superior Agates in the rough, you might take it home and crack it open to discover an Agate inside (right pix).
See some advice on using tumbling pellets to tumble and polish agates.
Books on Lake Superior Agate Hunting & Rock Picking
Recommended by a SuperiorTrails friend & rock hound, this new guide has actual photographs of various rocks and minerals found on Lake Superior beaches. Co-author Bob Lynch is owner of Agate City Rocks and Gifts in Two Harbors Minnesota
Karen Brzys. Director, Gitchee Gumee Agate & History Museum, is an experienced beach comber and agate collector. This is the most comprehensive book I've found on identifying and collecting agates. Most helpful has been the guidance on identifying agates-in-the-rough. [More Info]
This is required handbook for rock pickers who love to comb Lake Superior beaches looking for pretty rocks and hoping to find an agate. Identifies some of the UP's best rock picking beaches.
Here is another book recommended by a Superior Trails reader and rock hound who was able to identify over 50 rocks found on the beach using this guide by Kevin Gauthier and Bruce Mueller. Also included are tips for polishing the stones and rock. Kevin and Bruce also publish a similar guide for Lake Michigan rocks.
My wife Jo found this agate hunters book while traveling in the UP and thought it would help her find her first Lake Superior Agate. It is full of tips for agate hunting (and rock picking) and has some very good color photographs of a number of agate variations as well as photos of the other kinds of rocks you'll find on Lake Superior beaches.
Sparky's guide covers what north shore beaches to comb, a bit of history on the formation of the various rocks found on beaches, and helpful information and pictures on identifying beach rocks and minerals.
Roger Pabian, professor emeritus at the University of Nebraska-Lincoln, and his fellow authors provide an informative guide to finding and collecting agates.
We had a great time at our first festival. My wife Jo found 5 agates on the beach and is now an addicted agate hound!.
Links for Rock Picking on Lake Superior Beachs and information on Agates and Rocks found around Lake Superior
Continuing your Travel & Trekking
Around Lake Superior
Superior Trails Lake Superior Circle Tour
SuperiorTrails.com - Reinhold Development - 2015
Lake Superior Camping
& Campground Directory
Lake Superior Circle Tour Route
See the lighthouses on an Apostle Islands Cruise.