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Green Valley Tonalite Dark Variety
Field Collector: Esper Signius Larsen Jr.
Place Collected:San Luis Rey Quadrangle, Southern California
Object number: ROC21764
DescriptionPlutonic medium-grained (1-5 mm) igneous rock. Dark grey to black on a fresh surface and dark grey on a weathered surface. Roughly consists of equigranular dark grey-green plagioclase (probably labradorite) 50% (1-2 mm), black amphibole and pyroxene 30%, light grey quartz 15%, and black biotite 5%.
In Collection(s)