Publication at Faculty of Science |
2011
Abstract
The new mineral agricolaite, a potassium uranyl carbonate, occurs in vugs of ankerite gangue in gneisses in the abandoned Giftkiesstollen adit at Jáchymov, Czech Republic. It occurs as isolated equant irregular translucent grains to 0.3 mm with yellow color, pale yellow streak, and vitreous luster, is brittle with uneven fracture and displays neither cleavage nor parting.
Agricolaite is non-fluorescent. Mohs hardness is ~4.
It is associated with aragonite, brochantite, posnjakite, malachite, rutherfordine, and "pseudo-voglite". The mineral is monoclinic, space group C2/c, with a 10.2380(2), b 9.1930(2), c 12.2110(3) Å, β 95.108(2)o, V 1144.71(4) Å3, Z = 4.
The structure of agricolaite is identical to that of synthetic K4(UO2)(CO3)3.