Judging quality
Look for well-defined dark orbs in a green matrix. It is softer and slightly more porous than true jasper.
Sedimentary
Dark green and black orbicular stone built from fossilised cyanobacterial colonies — technically a stromatolite rather than a jasper. The swirling eyes give it an unmistakable reptilian look.

Look for well-defined dark orbs in a green matrix. It is softer and slightly more porous than true jasper.
Water and cloth; avoid acids.
The structures are among the oldest fossil forms on earth, built by microbes that oxygenated the atmosphere.
Cultural history, recorded as tradition rather than as medical or scientific claim.
See it in person
Both rooms are open six days a week, and there is always someone happy to pull pieces out of the case so you can compare them under the light.