Geology at Henry Administration Building
Bedford limestone comprises the first floor of this structure, built in 1911, while the other levels consist of brick with stone trim, and the lamps are made of oxidized copper.
However, the stone featured here makes up the exterior stairs on the Quad side. Each step is fashioned from several blocks of granodiorite, possibly the same stone used for the foundation of Foellinger Auditorium and the south steps of the Illini Union.
This granodiorite is uniformly medium-grained, which mean it has crystals that are small but big enough to see. The photo is approximately 10 cm across. It contains white feldspar, gray quartz, and black amphibole and was probably quarried near Warman, Minnesota. Igneous rocks such as granodiorite are strong and sturdy stones that withstand footsteps for decades.
Other places where you may examine stairways of granodiorite include the north entrances of Smith Music Hall (above left), Natural History Building (middle), and the patio on the south side of the Illini Union.
Further geological information about the Warman Granodiorite
Sources
- lllinois State Geological Survey
- Granodiorite image by E. Herrstrom
- UIHistories Image IDs 39514, 14277, 4880, and 42521
Image selection and text by Eileen A. Herrstrom 2014