State by State
- Specimen Number
Rough-quarried block of gray-pink granite showing mainly gray quartz and pink alkali feldspars. Close up shows minor gneissic layering in quartz with altered mafic minerals.
Igneous. Plutonic. Granitic. Granite. Pink.
- Location & Occurrence
Identified by Massachusetts survey as the Milford, Chelmsford, or Quincy Granite, likely from either Gloucester or Rockport. USGS Describes the Chemsford granite as a medium-grained, often gneissic, muscovite-bearing granite, which matches this specimen. It was one of many synorogenic intrusives during the Acadian Orogeny.
- Geologic Age Lower Devonian, roughly 390 Ma +/-.
- Geoheritage Granite like this was quarried widely in eastern Ma. Our specimen (#19), if it's the Quincy Granite, was associated with Bunker Hill Monument and the first railroad in the U.S., dating to 1826.