Birnessite (delta MnO2-3H2O) in a large spherulite in obsidian near Silver Cliff, Colorado

Fred A. Hildebrand

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Birnessite (delta MnO2-3H2O) in a large spherulite in obsidian near Silver Cliff, Colorado

Fred A. Hildebrand

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Abstract

Birnessite and cryptomelane were identified in the montmorillonitic border zone of a large spherulite in obsidian north of Silver Cliff, Colo. The manganese minerals contain no silver and probably formed more recently than argentian cryptomelane which is abundant in the manganiferous silver ores of the surrounding volcanic rocks.

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Journal of Research of the U.S. Geological Survey Article

Source-reported bounding extent: 38.14009228717221° to 38.173297728425034° latitude; -105.47801971435547° to -105.41999816894531° longitude. This indicates report coverage, not an exact sampling location. View area on OpenStreetMap.

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Fred A. Hildebrand. 1974. Birnessite (delta MnO2-3H2O) in a large spherulite in obsidian near Silver Cliff, Colorado. https://pubs.usgs.gov/publication/70232482

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