Granodiorite Porphyry
Field Collector: Esper Signius Larsen Jr.
Place Collected:Corona, Corona Quadrangle, Southern California
Object number: ROC21686
DescriptionPorphyritic igneous rock with 50% white blocky plagioclase (3 mm - 1 cm) phenocrysts 30% grey quartz (3 mm - 1 cm) phenocrysts, 1% black hornblende (3-9 mm) phenocrysts, 10% K-feldspar groundmass, 7% chlorite groundmass, and 2% epidote groundmass. Groundmass minerals are only visible in thin section.