LECOQITE-(Y), Na3Y(CO3)3{middle dot}6H2O, A NEW MINERAL SPECIES FROM MONT SAINT-HILAIRE, QUEBEC, CANADA
Bibliographic record
Abstract
Lecoqite-(Y), ideally Na 3 Y(CO 3 ) 3 ·6H 2 O, a new mineral species, was discovered at the Poudrette quarry, Mont Saint-Hilaire, Quebec, Canada. It is associated with microcline, albite, natrolite, gonnardite, aegirine, siderite, elpidite, gaidonnayite, zircon, franconite, dawsonite, rhodochrosite, cryolite, rutile, and sphalerite. Lecoqite-(Y) forms radiating, spray-like aggregates in compact, tightly packed masses to 2.5 cm across, composed of flexible, extremely thin, capillary crystals up to 2.5 cm long and up to 0.01 mm thick. Individuals are colorless, and aggregates are white. The luster is strikingly silky. D(calc.) = 2.358 g/cm 3 . Lecoqite-(Y) is optically uniaxial positive, ω = 1.521(3), e = 1.497(3). The IR spectrum is unique. The chemical composition (electron microprobe, H 2 O by modified Penfield method, CO 2 by selective absorption, average results) is: Na 2 O 19.22, CaO 0.03, Y 2 O 3 17.95, Nd 2 O 3 0.54, Sm 2 O 3 0.41, Gd 2 O 3 0.75, Dy 2 O 3 3.31, Ho 2 O 3 1.12, Er 2 O 3 3.20, Yb 2 O 3 1.48, CO 2 27.0, H 2 O 23.4, total 98.41 wt.%. The empirical formula calculated for 15 O apfu is: Na 2.94 (Y 0.755 Dy 0.085 Er 0.08 Yb 0.035 Ho 0.03 Gd 0.02 Nd 0.015 Sm 0.01 ) ∑1.03 (CO 3 ) 2.91 (OH) 0.21 (H 2 O) 6.06 . Lecoqite-(Y) is hexagonal, P 6 3 , a 11.316(4), c 5.931(2) A, V 657.7(4) A 3 , Z = 2. The crystal structure was established from X-ray powder data by the Rietveld method, based on the model of the isostructural synthetic Ln-free carbonate Na 3 Y(CO 3 ) 3 ·6H 2 O. Final agreement factors are: R p = 0.0468, R wp = 0.0657, R Bragg = 0.0343, R F = 0.0356. No mineral is closely related to lecoqite-(Y) in terms of structure. In the structure of lecoqite-(Y), REE atoms (REE = Y + Ln) are surrounded by six O atoms of CO 3 groups and three H 2 O molecules to form a tricapped triangular prism. The Na atoms are centered in distorted octahedra [NaO 4 (H 2 O) 2 ], which link to form infinite corrugated chains along c . The strongest five lines of the X-ray powder pattern [ d in A (I)( hkl )] are: 9.82(57)(100), 5.081(100)(101), 3.779(39)(201), 2.627(39)(112), 2.471(37)(131). Lecoqite-(Y) is named in memory of P.E. Lecoq de Boisbaudran (1838–1912), outstanding French chemist and specialist in the spectroscopic analysis of minerals and synthetic compounds, who made a great contribution to the chemistry of the rare-earth elements. The Levinson suffix modifier -(Y) is in line with the dominance of yttrium over other rare-earth elements in the mineral. The cotype specimens are deposited in the Fersman Mineralogical Museum of Russian Academy of Sciences, Moscow, and the Canadian Museum of Nature, Ottawa.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.007 | 0.001 |
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 source (direct Gemma or distilled Codex), 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".