ultra rare
datolite
calcium borosilicate
The tell
A dense, smooth nodule that looks like unglazed porcelain in white, cream, pink or orange, and is surprisingly heavy for its size.
Yes, it looks like a potato until it is cut. The cut face is why people chase it, and Keweenaw copper mine dumps are the source. Ask permission; most of them are on private land.
What it gets mistaken for
- thomsonite
- banded chert
- quartz
- potato
- concretion
The facts
- also calledcalcium borosilicate
- age~1.1 billion yrs
- where it turns upKeweenaw mine dumps ยท with permission
- on the chartultra rare · 150 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 150 datolite will ever be printed, then the run is retired.
10% of every order goes to the Roscommon County Animal Shelter.