Department of Earth and Environmental Science

Igneous Rocks:

Porphyritic Andesite

An intermediate igneous rock that is the extrusive equivalent of diorite. It is usually medium to dark grey. This specimen contains phenocrysts of amphibole set in an aphanitic groundmass.

Collections

History of the Collections

Overview of the Collections

Teaching Collections

• Teaching Demonstrations and Supplies
• Field Trip Supplies
• Earth Science Collections

Accessing the Collections

Collections Staff

Contact

Department of Earth and Environmental Science
240 S. 33rd Street
Hayden Hall
Philadelphia, PA
19104-6316

nmccann@sas.upenn.edu

(T) - 215-746-0086