CERITE-(La), (La,Ce,Ca)9(Fe,Ca,Mg)(SiO4)3[SiO3(OH)]4(OH)3, A NEW MINERAL SPECIES FROM THE KHIBINA ALKALINE MASSIF: OCCURRENCE AND CRYSTAL STRUCTURE
Bibliographic record
Abstract
Cerite-(La), ideally (La,Ce,Ca) 9 (Fe,Ca,Mg)(SiO 4 ) 3 [SiO 3 (OH)] 4 (OH) 3 , was found in an aegirine – natrolite – microcline vein in foyaite, Mt. Yuksporr, Khibina massif, Kola Peninsula, Russia. It forms porous pseudomorphs (up to 7 cm long) after an unidentified hexagonal prismatic mineral. Within the pseudomorphs, cerite-(La) occurs as a boxwork-like aggregates of equant to tabular crystals (flattened on c , up to 2 mm across), with dominant rhombohedral and pinacoidal faces. Associated minerals are aegirine, anatase, ancylite-(Ce), barylite, catapleiite, cerite-(Ce), chabazite-Ca, edingtonite, fluorapatite, galena, ilmenite, microcline, natrolite, sphalerite, strontianite and vanadinite. The mineral is brittle, with a conchoidal fracture. It is light yellow to pinkish brown with a white streak, and translucent with a vitreous luster. Cleavage and parting were not observed. The Mohs hardness is 5; the density is 4.7(1) g cm −3 (meas.) and 4.74 g cm −3 (calc.). It is uniaxial, optically positive, n o 1.810(5), n e 1.820(5) (for λ = 589 nm). An average result of seven electron-microprobe analyses for seven different crystals (each one reported as an average of 6–10 points from each crystal) gave La 2 O 3 37.57, Ce 2 O 3 23.67, Pr 2 O 3 0.61, Nd 2 O 3 1.48, Sm 2 O 3 0.10, Gd 2 O 3 0.24, SrO 1.97, CaO 5.09, Fe 2 O 3 1.40, MgO 0.51, SiO 2 22.38, P 2 O 5 0.63, H 2 O 3.20 (determined by the Penfield method), total 98.85, which corresponds to the empirical formula (La 4.23 Ce 2.65 Ca 1.37 Sr 0.35 Nd 0.16 Pr 0.07 Gd 0.02 Sm 0.01 ) ∑8.86 (Fe 0.32 Ca 0.30 Mg 0.23 ) ∑0.85 [SiO 4 ] 3 [(Si 0.84 P 0.16 ) ∑1.00 O 3 (OH)] 4 (OH) 2.78 , calculated on the basis of (Si + P) = 7. The mineral is trigonal, R 3 c , with a 10.7493 (6), c 38.318 (3) A, V 3834.36 A 3 , Z = 6. The strongest eight lines in the X-ray powder-diffraction pattern [ d in A( I )( hkl )] are: 3.53(26)(10.10,211), 3.47(40)(122), 3.31(38)(214), 3.10(25)(300), 2.958(100)(02.10), 2.833(37)(128), 2.689(34)(220), 1.949(34)(238,13.13). The crystal structure has been refined on the basis of F 2 for all unique reflections collected using a CCD area detector, to an R 1 of 0.036, calculated for the 1544 unique observed reflections ( F o ≥ 4σ F o ). Cerite-(La) is structurally related to cerite-(Ce). The mineral is named as the La-dominant analogue of cerite-(Ce). The structural formula for these minerals can be written as REE 9 M Ca x [SiO 4 ] 3 [SiO 3 ((OH) 1− x O x )] 3 [SiO 3 (OH)] 1− x (OH) 3 , where REE stands for La or Ce, and where M represents Fe, Mg, Ca.
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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 | 0.000 |
| Science and technology studies | 0.000 | 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 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".