Also found in: Dictionary, Wikipedia.


Ca(UO2)2(PO4)2·10H2O A common fluorescent mineral that occurs as yellow tetragonal plates in uranium deposits; minor ore of uranium.



(named after the city of Autun, in Saône-et-Loire Department France), a mineral of the uranite group. Autunite has a chemical formula of Ca(UO2)2[PO4]2·8H2O; it contains 62.7 percent UO3. The mineral crystallizes in the tetragonal system, primarily forming thin tabular, micaceous, or tetragonal crystals. Scaly aggregates also occur. Autunite varies in color from lemon yellow to sulfur yellow; sometimes it is green. The mineral has a pearly luster and is highly radioactive. Its hardness on Mohs’ scale is 2–2.5, and its density is 3,050–3,190 kg/m3. Autunite is formed as a result of surface changes in various uranium minerals (particularly uraninite), in hydrothermal veins, and in pegmatites. It is an ore of uranium.

References in periodicals archive ?
The other associated hydrothermal minerals are epidore, titanite, chlorite, muscovite, tourmaline, and minor amounts of opaque minerals such as sphalerite, chalcopyrite, uraninite, and autunite.
The strongly sheared samples (such as sample 139, Table 2) have geochemical characteristics comparable to the mineralized zones containing chalcopyrite, pyrite, sphalerite, and autunite from the Millet Brook deposit (Chatterjee and Strong 1984), although the alteration intensity and elemental enrichment are much less pronounced in the drill core samples (Table 1).