rare
lake superior agate
Chalcedony (SiO2)
The tell
Concentric bands that follow the shape of the cavity the agate grew in (sharp lines, not fuzzy ones), plus translucency at any thin edge.
If it does not pass light and the bands are soft-edged parallel stripes, it is banded chert. This is the single most common misidentification on the lake.
What it gets mistaken for
- banded chert
- carnelian
- red jasper
- banded chert
- thunder egg
The facts
- also calledChalcedony (SiO2)
- age~1.1 billion yrs
- where it turns upSuperior shore best ยท float south, rarer
- on the chartrare · 250 stickers ever
Put it on the shelf
Every stone on this chart is drawn and kiss-cut at three inches. The rarer the stone, the fewer exist: only 250 lake superior agate will ever be printed, then the run is retired.
10% of every order goes to the Roscommon County Animal Shelter.