State by State
Delaware
- Specimen Number
7
- Description
Cut block of dimension stone inscribed with the name "DELAWARE."on a smooth, but not polished, face. Identified by state survey staff as likely the Brandywine Blue Gneiss, a formation of "medium to coarse grained granulites and gneisses composed of plagioclase, quartz, orthopyroxene, clinopyroxene, brown-green hornblende, magnetite, and ilmenite."
- Classification
Metamorphic. Gneiss. Granitic.
- Location & Occurrence
Located by survey staff as likely from near Brandywine Creek. Our specimen is definitely layered, but not blue, a high-grade, mountain root, dynamothermal, metamorphic rock.
- Geological Age
Ordovician.
- Geoheritage
Northern part of Delaware is underlain by hard, Appalachian rocks.
- Links
Link to State Geological Map from USGS. Link to State Geological Survey. Link to Unit Obbg at Delaware Survey.
- Other
This is an example of a rock that would never have been located without the assistance of a state survey.
Click here for an explanation of categories and illustrations
![Specimen stone for Deleware.](https://earthsciences.media.uconn.edu/wp-content/uploads/sites/3541/2022/10/07aa_Delaware_210927a276.jpg)
![Closeup of Deleware](https://earthsciences.media.uconn.edu/wp-content/uploads/sites/3541/2022/10/07bb_Delaware_210927a277.jpg)
![Outline of Deleware width=](https://earthsciences.media.uconn.edu/wp-content/uploads/sites/3541/2022/10/Delaware-OutineUS.jpeg)
![Geo Map of Deleware](https://earthsciences.media.uconn.edu/wp-content/uploads/sites/3541/2022/10/Deleware-USGS-OFR-2005-1325.jpg)