Argentian cryptomelane and bromargyrite in volcanic rocks near Silver Cliff, Colorado
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Geology topics
Fred A. Hildebrand
Publications and source records attributed to Fred A. Hildebrand.
Coloradoite, acanthite, and jarosite from the Cripple Creek district, Teller County, Colorado
Coloradoite (HgTe), acanthite (Ag 2 S), and jarosite (KFe 3 (S0 4 ) 2 (OH) 6 ) have been identified in rocks from the Cripple Creek district, Colorado. Neither acanthite nor jarosite has previously been reported from this mining district. Although the occurrence of coloradoite was reported, its identification was never actually verified. The presence of acanthite may explain a discrepancy between the relative proportions of gold and silver as shown by mill reports and geochemical data.
Colorado↗
Birnessite (delta MnO2-3H2O) in a large spherulite in obsidian near Silver Cliff, Colorado
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.
Colorado↗