Alteration (silicification) typical of early White porphyry; note extensive development of coarse secondary grainlets of quartz, with inclusions and absence of true phenocrysts. Lake County, Colorado. 1935.
Dates
Date Taken
1935
Summary
Alteration (silicification) typical of early White porphyry; note extensive development of coarse secondary grainlets of quartz, with inclusions and absence of true phenocrysts. X 33; crossed nicols; from Great Eastern shaft, near Lake Isabelle. Lake County, Colorado. 1935. Figure 28, in U.S.Geological Survey Professional paper 235. 1953.
Summary
Alteration (silicification) typical of early White porphyry; note extensive development of coarse secondary grainlets of quartz, with inclusions and absence of true phenocrysts. X 33; crossed nicols; from Great Eastern shaft, near Lake Isabelle. Lake County, Colorado. 1935. Figure 28, in U.S.Geological Survey Professional paper 235. 1953.
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