Nickeltyrrellite, CuNi2Se4, a new member of the spinel supergroup from El DragÓn, Bolivia
Why this work is in the frame
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Bibliographic record
Abstract
Abstract Nickeltyrrellite, ideally CuNi2Se4, is a new selenide species from the El Dragón mine, Department of Potosí, Bolivia. It most frequently occurs as anhedral to subhedral grains (up to 20 μm in size) in association with cerromojonite, klockmannite, clausthalite, and penroseite, forming fracture fillings in pre-existing krut'aite−penroseite solid solutions. Nickeltyrrellite is non-fluorescent, black, and opaque with a metallic luster and black streak. It is brittle, with an irregular fracture and no obvious cleavage and parting. In plane-polarized incident light, nickeltyrrellite is cream to pale pinkish, displaying no internal reflections. Between crossed polarizers, it is isotropic. The reflectance values in air for the COM standard wavelengths are 45.9 (470 nm), 47.6 (546 nm), 48.1 (589 nm), and 49.8 (650 nm). Electron-microprobe spot analyses (n = 28) of the grain populations used for the EBSD study yielded a mean composition of Cu 13.01, Fe 0.27, Co 6.66, Ni 16.98, S 1.04, Se 61.91, total 99.87 wt.%. The empirical formula, normalized to 7 apfu, is Cu1.00(Ni1.42Co0.56Fe0.02)Σ2.00(Se3.84S0.16)Σ4.00. The ideal formula is CuNi2Se4, which requires (in wt.%) Cu 12.79, Ni 23.63, Se 63.58, total 100. EBSD patterns reveal nickeltyrrellite as cubic, space group , with a = 9.99 Å, V = 997.0 Å3, Z = 8. The calculated density is 7.36 g cm−3. It formed in response to alteration of quijarroite + hansblockite + watkinsonite + clausthalite + penroseite aggregates by oxidizing, low-T, Cu-Ni-Co-Pb-bearing fluids at a fSe2/fS2 ratio greater than unity. Nickeltyrrellite is a new selenide belonging to the tyrrellite subgroup of the spinel supergroup. The new species has been approved by the IMA-CNMNC (2018-110) and is named for constituting the Ni-analogue of tyrrellite.
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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 | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.005 | 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 it