State by State
- Specimen Number
Block of roughly quarried gray granite with pink alkali feldspars. Verified by Maine Geological Survey. Crimson-colored stains blotch the rock in the vicinity of pink feldspars but grow over other crystals.
Igneous. Plutonic. Granitic. Granite.
- Location & Occurrence
Likely from Aroostook County because that name is carved on the county's icon, a potato carved into the specimen. But the rock is common enough to have been collected from many places in Maine and other states. The state survey was reluctant to suggest a specific source. Mount Katahdin, a laccolith intrusion of granite located in Aroostook county, is underlain by such rock, and is thus a plausible source.
- Geological Age
Acadian orogeny, with widely scattered dates from 388-414 Ma (USGS source below)
Plausibly from Katahdin Granite, core of northern Appalachians, the rock on which Henry D. Thoreau experienced a widely known epiphany about the role of humans in the universe. Nearby Millinocket was reportedly the fastest growing city in the US in the 1930s.
Quoting the Hartford Courant 1937, specimen 17 is a "granite on which had been carved a potato bearing the carved word 'Aroostook.'" .