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Bonsall Tonalite
Field Collector: Esper Signius Larsen Jr.
Place Collected:Near Box Springs, Elsinore Quadrangle, California
Object number: ROC21700
DescriptionPlutonic, medium-grained (1-5 mm) igneous rock that is white-light tan on a fresh surface with flecks and clusters of black minerals (1 mm - 1.5 cm). Consists of 40% white plagioclase feldspar (1-4 mm), 30% light-grey quartz (1-5 mm), 15% K-feldspar, 10% black biotite (1-3 mm), and 5% black hornblende (≤ 1 cm) (roughly estimated visual modes).
In Collection(s)