Hydrotermálny bastnäsit-(Ce) zo štôlne Elisabeth pri Gemerskej Polome (Slovenská republika)

Bastnäsite-(Ce), ideally CeCO3F, was recently found at the dumps of the Elisabeth adit near Gemerská Poloma, Rožňava Co., Košice Region, eastern Slovakia. It forms orange-brown aggregates up to 2 × 1 cm with vitreous to greasy lustre, which occur in the hydrothermal quartz veins crosscutting the coarse-grained, porphyritic rare metal S-type granite. Bastnäsite-(Ce) is closely associated with white, pale-green to purple fluorite, siderite and minor pyrite. It is hexagonal, space group P-62c with refined unit-cell parameters: a 7.1354(1) Å, c 9.7954(2) Å and V 431.90(1) Å3. The empirical formula of bastnäsite-(Ce) from the Gemerská Poloma based on sum of all cations = 1 apfu is (Ce0.49 La0.22Nd0.15Pr0.05Sm0.03Th0.02Ca0.02Gd0.01Y0.01)Σ1.00(CO3)1.00F0.83(OH)0.17. The Raman and infrared spectra of bastnäsite-(Ce) as well as tentative assignment of observed bands are given in this paper. Bastnäsite-(Ce) and associated minerals were formed from the early-hydrothermal post-magmatic fluids related to the adjacent granite.