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Granodiorite
Field Collector: Esper Signius Larsen Jr.
Place Collected:San Luis Rey Quadrangle, Southern California
Object number: ROC21709
DescriptionPlutonic, medium-grained (1-5 mm) igneous rock that is white-light-grey with some lage black crystals of hornblende and biotite. Consists of ~35% light-grey quartz (≤ 2 mm), 30% white plagioclase (≤ 5 mm), 25% light pink-white K-feldspar (≤ 4 mm), 5% tabular black biotite (≤ 5 mm), and 5% black hornblende (≤ 5 mm).
In Collection(s)