Lake Superior Agate — Iron-Banded Fortification Pattern, Glacial Tumbled, 52g — Field Find

THE FIND
A Lake Superior agate, 52g — warm reds, oranges, browns, and creams in the characteristic iron-stained fortification banding. Naturally tumbled by glacial action. A smaller companion to the 155g specimen in the collection, with the same geological story in a more compact, hand-friendly form.

WHAT WE KNOW
Lake Superior agates are a specific variety of fortification agate formed approximately 1.1 billion years ago in the basaltic lava flows of the Midcontinent Rift System. The characteristic iron-rich banding (burnt reds, oranges, and browns) is produced by hematite and goethite deposited in the silica bands during formation. The stones were later transported and naturally tumbled by the Laurentide Ice Sheet during the Pleistocene glaciations, distributing them across Minnesota, Wisconsin, Iowa, and the Great Lakes region. This specimen weighs 52g. Locality attributed to the Lake Superior region.

THE STORY
Lake Superior agates are among the oldest agates on Earth — formed 1.1 billion years ago in a rift that nearly split the North American continent in two. The rift failed, the lava cooled, and the agates formed in the cavities. Then, roughly 10,000–20,000 years ago, glaciers picked them up and carried them south, tumbling and polishing them in the process. At 52g this specimen is a hand piece — compact enough to carry, substantial enough to examine. The iron banding is the color of a billion years of geological history.

WHY WE CHOSE IT
The fortification banding is well-developed and the iron-red coloration is warm and saturated. At 52g it sits at a practical size for carrying or desk display — lighter and more accessible than the 155g specimen, with the same geological credentials. A strong entry point into Lake Superior agate collecting.

ABOUT THIS PIECE
Type: Lake Superior agate (fortification agate, iron-banded chalcedony)
Origin: Lake Superior region, Upper Midwest
Weight: 52g
Condition: Naturally tumbled specimen — please review photographs for banding, color, and natural variation.
Quantity: 1 — one of a kind.