Brown fortification patterns are unusual in Lake Superior agate. In this agate the pinkish-tan hues in the center are also striking. It was found near Roberts,WI.
The "Dune Pattern" is rare in Lake Superior agates. This one comes from River Falls, WI
Here's one that puzzles agate formation theorists. It's a half-inch slab that is backlit. The front face of the agate is smooth except for the small opening of an oval cavity. The dark projections outward from the center cavity do not penetrate the husk. Are they entrance or exit tubes??? Hmmm...I doubt it.
Yes! It is a Lake Superior agate from Sedar Bay beach in Keweenaw County, MI. The black outer ring is opaque. The inner layers are translucent. Perhaps it's humanity's first glimpse of the interior of the black hole referred to by astronomers.
"Limestone Agate" chiseled out of a limestone boulder found in a dry-wash near River Falls, WI. Its coloring is unusual and it has no fractures.
The jagged outer pattern indicates this agate was not tumbled by rushing glacial waters. It was mine from a reef on the Northeast coast of Isle Royale, MI....MANY MANY YEARS AGO