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Porphyritic Basalt
Field Collector: Esper Signius Larsen Jr.
Place Collected:Elsinore Quadrangle, Southern California
Object number: El 36-4
DescriptionBlack porphyritic volanic rock with grey plagioclase phenocrysts (~2 mm) and skeletal augite phenocrysts that aren't apparent in hand sample. The groundmass is composed of 50% bownish glass and 50% plagioclase (~0.01 mm) difficult to see even in thin section.
In Collection(s)