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

July 1, 1974
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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.

Citation Information

Publication Year 1974
Title Birnessite (delta MnO2-3H2O) in a large spherulite in obsidian near Silver Cliff, Colorado
Authors Fred A. Hildebrand
Publication Type Article
Publication Subtype Journal Article
Series Title Journal of Research of the U.S. Geological Survey
Index ID 70232482
Record Source USGS Publications Warehouse