What does autunite mean?
Autunite is a bright yellow mineral composed of hydrated calcium uranyl phosphate, best known to mineralogists as one of the more common secondary minerals formed in the oxidation zones of uranium deposits. It typically occurs as small tabular or platy crystals arranged in rosette-like clusters, and it is prized by collectors for its striking fluorescence: when exposed to ultraviolet light, autunite glows an intense yellow-green. The mineral takes its name from Autun, the French town near which early specimens were first described in the nineteenth century. Although historically significant as a uranium ore, autunite is only mildly radioactive and is valued today chiefly as a collector's specimen and indicator mineral in exploration. Because it loses water readily, well-preserved crystals require careful storage. The name appears almost exclusively in scientific, mining, and collecting contexts rather than general vocabulary.
nounA yellow fluorescent mineral, a hydrated calcium uranyl phosphate (Ca(UO₂)₂(PO₄)₂·10–12H₂O), occurring in tabular crystals and typically found in the oxidation zones of uranium deposits.
- A yellow fluorescent hydrated calcium uranyl phosphate mineral, an important secondary uranium ore found in the oxidized zones of uranium deposits.
"Under the ultraviolet lamp, the specimen of autunite glowed a vivid yellow-green."
"The prospector identified the autunite by its lemon-yellow tabular crystals and strong green fluorescence."
"Because autunite dehydrates readily, museum specimens are often kept sealed to preserve their crystal structure."
Rarely pluralized; the plural is used mainly when referring to multiple distinct specimens or occurrences of the mineral.
"The drawer contained several autunites collected from sites across Europe."
Autunite fluoresces so brilliantly under UV light that collectors call specimens 'lemon slices' — but handle with care, since it's mildly radioactive and sheds radon.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of autunite
Autunite was named after Autun, a town in the Burgundy region of France where notable specimens were found, and was first described in the mid-nineteenth century following work by French mineralogists. The suffix '-ite' follows the standard convention for naming minerals after places or people. As a uranyl phosphate, it belongs to the same mineral group as torbernite and metatorbernite, its copper-bearing analogues.
How autunite is actually used
A technical term used mainly in mineralogy, geology, and the nuclear/uranium-mining industries; rare in everyday speech. Because it is radioactive, handling notes often accompany discussion of specimens.
Easily confused with autunite
Torbernite is a closely related uranyl phosphate in which copper replaces calcium as the cation, giving it a green rather than yellow colour.