FELBERTALITE AND RELATED BISMUTH SULFOSALTS FROM THE FUNIUSHAN COPPER SKARN DEPOSIT, NANJING, CHINA
Bibliographic record
Abstract
Electron-microprobe and single-crystal X-ray-diffraction analyses have confirmed the second occurrence of felbertalite in the Funiushan copper skarn deposit, near Nanjing, in eastern China. It can be chemically described as Cu2AgxPb6–2xBi8+x(S,Se)19, with a wide range of substitution of Bi + Ag for 2Pb, with x ranging from 0.64 to 1.03 (probably up to 1.33), suggesting the presence of a solid-solution series in felbertalite. The measured unit-cell parameters of a felbertalite grain with a composition of Cu2.20Ag0.70Pb4.65Bi8.45S19.12 are: a 27.68(4), b 4.046(1), c 20.67(3) Å, 131.06(8)°, space group C2/m. A set of phases in the bismuthinite–aikinite series, mostly free of Ag and characterized by intermediate compositions between ideal formulae, were identified with electron-microprobe data. Compositional variations from Cu1.80Pb1.80Bi2.20S6, through Cu1.53Pb1.53Bi2.47S6, Cu1.07Pb1.07Bi2.93S6, Cu0.73Pb0.73Bi3.27S6, to Cu0.58Pb0.58Bi3.42S6 within a single grain were observed, indicating that an intergrowth of three structural units, i.e., bismuthinite ribbons, krupkaite ribbons and aikinite ribbons, could occur in the progressive exsolution or precipitation of a single phase in the bismuthinite–aikinite series. The exceptionally high contents of Ag (0.76–1.27 wt%) in the phase Cu0.83Ag0.10Pb0.90Bi3.13S6, presumably corresponding to krupkaite, are noted. Electron-microprobe analyses have also revealed the occurrence of a number of rare minerals, including junoite, unknown Cu2AgxPb10–2xBi12+xS29 (1.23 < x < 1.49), berryite, benjaminite?, schirmerite?, Bi- and Ag-bearing galena, wittichenite and tetradymite. Within the intergrowths of Cu–Ag–
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".