Gysinite-(Nd) mineral

A natural lead-neodymium carbonate mineral of the ancylite group, distinct from its La- and Ce- dominant counterparts and from synthetic Pb-free Nd carbonates. The September 2026 IMA list gives PbNd(CO3)2(OH)(H2O), status renamed and 1987 special procedure; that date records nomenclature action, not a species-specific approval accession. Sarp and Bertrand's 1985 original description used the name gysinite and a Geneva museum specimen, catalogue 410/85, labelled schuilingite from Shinkolobwe. Deliens and Stalder's 1995 type catalogue instead assigns the material to Kasompi copper mine because its mineral association is characteristic of Kasompi; it lists Geneva 410/85 and 435/60. The original label and later reassignment are retained as provenance evidence, not a newly verified collection locality. The original study's diffraction supports orthorhombic Pmcn; film-derived cell estimates and subsequently refined cell parameters are separate measurements. Its 21 microprobe analyses found Nd-dominant Pb-La-Nd chemistry with slight variation and no particular zoning. Carbon was measured, but water was obtained by difference. The reported combined thermogravimetric CO2-plus-water loss of about 23 wt.% differs from the 26.2 wt.% sum of the Table 2 mean components; the paper calls this agreement, but the record does not reconcile the difference or treat the empirical hydration as exact. Its 4.82 g/cm3 density is calculated, not measured. Effervescence in cold dilute HCl is a qualitative observation without a quantified dissolution or recovery experiment. The proposed geological REE source was an interpretation, not a controlled transformation. The separately cited 1985 atomic refinement and its original reflection data were not acquired here; no site occupancies or hydrogen positions are adopted from secondary summaries. No criticality designation, microbial mechanism or industrial recovery is asserted.

Record source: data/records/gysinite-nd.yaml