the bedrock
rhyolite
feldspar porphyry
The tell
Big blocky feldspar crystals floating in a fine, almost glassy background. Granite is crystalline everywhere you look; rhyolite has crystals sitting in something smooth.
Same chemistry as granite, cooled fast instead of slow. It is what granite would have been if it had reached the surface.
What it gets mistaken for
- granite
- red jasper
- porphyry
- felsite
The facts
- also calledfeldspar porphyry
- age~1.1 billion yrs
- where it turns upevery shore ยท glacial float
- on the chartthe bedrock · 1000 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 1000 rhyolite will ever be printed, then the run is retired.
10% of every order goes to the Roscommon County Animal Shelter.