Crandallite and florencite-(Ce) from a quartz vein of the area Zhelannoye Deposit (Subpolar Ural)

[Marco E. Ciriotti]

Referenza:
▪ Repina, S.A. (2023): Crandallite and Florencite-(Ce) from a Quartz Vein of the Area Zhelannoye Deposit (Subpolar Ural). Zapiski RMO, 152(4), 84-98.

Abstract:
The article discusses minerals from the plumbohummite–crandallite and florencite-(Ce) group. The minerals were found on a fragment of a hematite aggregate extracted from the lower pinching out of a quartz vein of the Zone 25 occurrence. The occurrence is located in close proximity to the deposits of the Zhelannye rock crystal vein quartz and Chudnoe Au-Pd-REE. Crandallite deposits are presented in two forms: rhombohedral crystals and spherulites. Three generations of this mineral are distinguished: the first - rhombohedral crystals, the second - crusts on the faces of rhombohedrons, the third - crandallite spherulites on the surface of rhombohedrons. The crusts are 150 µm thick and consist of four layers: REE-containing crandallite, symplectite intergrowths of crandallite with florencite (Ce), spherulites and crandallite powder crystals. The first and second generations of minerals crystallized from solutions, the third was rescheduled. Generations of crandallite differ in the content of impurities Sr, Ba, REE, U, Fe, S, Si.