Gummite
Image: James St. John (CC BY 2.0)
Mineral NameGummite
Chemical FormulaA complex mix of secondary uranium minerals (oxides, silicates, carbonates)
Crystal Systemamorphous
Lustervitreous
Streak Coloryellowish-orange
Cleavagenone
Fractureuneven
Colorsyellowish, orange
Transparencyopaque to translucent
Type LocalityRuggles Mine, Grafton Center, New Hampshire, USA
Mineral GroupSecondary Uranium Minerals (mix of oxides, silicates, carbonates)
Usescollector's item, scientific study
Associated Mineralsuraninite, fourmarierite, clarkeite, kasolite
Rarityuncommon
Description
Gummite is a radioactive, yellowish- to orangish-colored mix of uranium-bearing minerals. It is fine-grained, massive, and somewhat tacky, often with black grains of unaltered uraninite.
Geological Context
Gummite forms as a secondary alteration product in the oxidation zone of uranium deposits, resulting from the oxidation of primary uraninite (uranium dioxide).
