Outstanding yellow-green crystals of the very rare uranium mineral agricolaite from the famous Jachymov district (Jáchymov, Krušné Hory, Karlovy Vary Region, Czech Republic). Ex. Erich Laskowski collection (USA). — Photo: David Hospital · CC BY 4.0
Agricolaite
Agricolaite is an IMA-recognized mineral species in the carbonate class, with the chemical formula K₄(UO₂)(CO₃)₃.
It crystallizes in the monoclinic crystal system (space group C2/c).
Key properties: Mohs hardness 4; specific gravity 3.3; Pale yellow streak; Vitreous luster.
IMA symbol Agc, IMA status: approved, named in 2009.
A secondary weathering mineral in vugs of ankerite gangue in gneiss.
It is found associated with Aragonite, brochantite, posnjakite, malachite, rutherfordine, “pseudo-voglite”.
The mineral was named to honor Georgius Agricola (1494-1555), German scholar and scientist, “Father of Mineralogy”, and author of De re Metallica Libri XII (1556).