Deep yellow microcrystals of the extremely rare Al-U mineral ranunculite from the TL and only confirmed locality worldwide (Kobokobo Pegmatite, Mwenga, South Kivu, DR Congo). Ex Vandenbroucke Museum collection from Waregem, Belgium. — Photo: David Hospital · CC BY-SA 4.0
Ranunculite
Ranunculite is an IMA-recognized mineral species in the phosphate class, with the chemical formula Al(UO₂)(PO₃OH)(OH)₃·4H₂O.
It crystallizes in the monoclinic crystal system.
Key properties: optically biaxial.
IMA symbol Rnu, IMA status: approved, named in 1978.
A rare secondary mineral found in the oxidized uraniferous zone of a complex granite pegmatite.
It is found associated with Meta-autunite, phosphuranylite, phuralumite, upalite, moreauite, threadgoldite.
The name refers to resemblance of the mineral's color to that of the buttercup, ranunculus in Latin.