The Lake Superior Agate is Minnesota’s state gemstone, and for good reason. These banded stones are gorgeous when polished, made into jewelry, or even straight from the beach. With constant waves on Lake Superior, there is never a shortage of new rocks to search through. Agates make a wonderful souvenir of the North Shore.
You can find – or at least search for – agates at a number of different beaches. Head down to the water — some people like to wade in, but be warned, Lake Superior is never particularly warm. Agates are easier to identify when wet, good thing you’re looking next to the largest body of fresh-water in the world!
The best time to look for agates is after a storm or an exceptionally windy and wavy day on the lake. The waves will push new rocks from the lake up onto the beach. If you really want to get into the agate hunt, bring some tools: a gardener’s hand rake/cultivator and a magnifying glass will make searching and identifying your prize easier.
Listed by mile marker [mm]from the southwest to the northeast.
To find these locations on a map, click here for a North Shore of Lake Superior map.
Can’t find any agates on the beach? Many shops along the North Shore sell agates, mostly as jewelry, but you can find whole agates for sale too.
Most Lake Superior agates started to form around 1.1 billion years ago by sulfur and carbon dioxide bubbles in the lava that formed the landscape. These bubbles slowly filled in with layers of other minerals that form the agates we see today. Each band in agate is from a different mineral, and most agates are 99% Microcrystalline Quartz. When you see the orange, rust, brick-red bands, you are seeing rusty iron.
Agates are much harder than the rocks they are formed in, so as the softer basalt and rhyolite erode around them, they come free and wash up on our beaches. The largest-ever Lake Superior agate was over 110 pounds, the size of a small adult.
If you want a pretty, shiny agate, drop them into water. Another common practice is to put agates through a rock tumbler to polish and round them. Some people cut them with a rock saw or break them open to reveals the bands within them, too.