Uranophane
Uranophane is a bright yellow calcium uranyl silicate hydrate that forms as a secondary mineral through the oxidation and alteration of uraninite and other primary uranium ores. Chemically it is Ca(UO2)2(SiO3OH)2·5H2O, and it typically appears as radiating sprays, fibrous tufts, or fine acicular crystals coating matrix, often alongside gummite and other uranium alteration products. As the type species of the uranophane group, it is closely related to boltwoodite and sklodowskite, and a rarer polymorph, uranophane-beta, is also recognized by collectors.
Classic, richly crystallized specimens come from the Madawaska Mine near Bancroft, Ontario, long famous for lustrous yellow uranophane on pegmatite matrix. Exceptional Brazilian material is found at Teófilo Otoni, Minas Gerais, where vivid yellow crystals accompany black uraninite, while the Rössing mine in Namibia and the legendary Shinkolobwe deposit in the Democratic Republic of Congo have both yielded historically significant uranophane on uranium-rich matrix.
Collectors seek uranophane for its striking canary-yellow color, delicate fibrous habit, and fluorescent glow under shortwave UV light, as well as its importance as a diagnostic secondary uranium mineral. Because it is radioactive, specimens are prized in specialized radioactive-mineral collections and typically kept in small, well-documented lots reflecting locality and crystal quality.
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Product type
Minerals collector specimens · Masterpiece our finest pieces · Decorative minerals · Crystal healing
Origin
Continent, country or Italian region where the specimen was found.
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TOP, Aesthetic, Radioactive, Fluorescent, Phosphorescent, Pseudomorphosis, Rare, Rare locality, New find, Systematic, Topographic, Historic.
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Crystal, Crystal cluster, Crystals on matrix, Geode, Massive, Free form, Polished, Slice, Mineral lot.
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