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Aguanga tonalite
Field Collector: Esper Signius Larsen Jr.
Place Collected:Oak Grove, Ramona Quadrangle, California
Object number: ROC21707
DescriptionPlutonic, medium grained (1-5 mm) igneous rock that is light tan on a fresh surface with many flecks of black biotite throughout. This rock consists of ~50% light-tan plagioclase (1-3 mm), 25% light grey quartz (1-3 mm), 10% black biotite (≤ 5 mm), 10% black hornblende (1-3 mm), and 5% K-feldspar (indistinguishable in hand sample).
In Collection(s)