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Granodiorite of El Salto
Field Collector: Esper Signius Larsen Jr.
Place Collected:Cerro de la Calavera, San Luis Rey Quadrangle, California
Object number: ROC21690
DescriptionPlutonic, medium-grained (1-5 mm) igneous rock that is medium-dark faintly blue grey on a fresh surface and slightly darker grey on a weathered surface. Consists of 50% dark grey-blue feldspar (1-4 mm), and 50% light-grey quartz (1-2 mm) with trace amounts of biotite. In thin section K-feldspar becomes an apparent constituent, making up a little over 5% of the rock. Also seen in thin section, epidote and biotite are associated with magnetite, but make up less than 2% of the rock.
In Collection(s)