Torbernite
Image: <a href="//commons.wikimedia.org/wiki/User:Archaeodontosaurus" title="User:Archaeodontosaurus">Didier Descouens</a> (CC BY-SA 4.0)
Mineral NameTorbernite
Chemical FormulaCu(UO₂)₂(PO₄)₂·8-12H₂O
Mohs Hardness2.5
Crystal Systemtetragonal
Lustervitreous
Streak Colorpale green
Cleavageperfect on {001}
Fractureuneven
Specific Gravity3.4
Colorsemerald-green, grass-green, apple-green
Transparencytransparent
Type LocalityMargabal Mine, Entraygues-sur-Truyère, Aveyron, Midi-Pyrénées
Mineral Groupphosphates
Usescollector, minor uranium ore
Associated Mineralsautunite, uraninite, quartz, feldspar
Rarityuncommon
Description
This specimen features numerous bright emerald-green, square-tabular crystals of torbernite, ranging from small to larger, well-formed individuals, covering a dark, possibly granitic matrix.
Geological Context
Torbernite is a secondary uranium mineral that forms in the oxidized zones of uranium-bearing ore deposits, often found in granitic pegmatites or hydrothermal veins where primary uranium minerals have altered.
