Crandallite and Florencite-(Ce) from a Quartz Vein of the Area of the Zhelannoe Deposit, Subpolar Urals

The paper considers the minerals of the plumbogummite group: crandallite and florencite-(Ce). The minerals are found on a fragment of a hematite aggregate sampled from the lower pinch out of a quartz vein of the Zona 25 occurrence. The occurrence is located in the direct vicinity of the Zhelannoe quartz and Chudnoe Au–Pd–REE deposits. Crandallite occurs as rhombohedral crystals and spherulites. Three generations of the mineral are recognized: (1) rhombohedral crystals, (2) crusts on rhombohedra faces, and (3) spherulites on rhombohedra surface. The crusts 150 µm thick consist of four layers: REE-bearing crandallite, symplectites of crandallite and florencite-(Ce), spherulites, and late crandallite crystals. The first and second generations of minerals crystallized from fluids, and the third generation is redeposited. The crandallite generations differ in Sr, Ba, REE, U, Fe, S, and Si content.