CORDYLITE-(La), A NEW MINERAL SPECIES IN FENITE FROM THE BIRAYA Fe-REE DEPOSIT, IRKUTSK, RUSSIA
Bibliographic record
Abstract
Cordylite-(La), (Na,Ca)2Ba2(La3Sr)∑4(CO3)8F2, is a new mineral species (IMA2010–058) from the Biraya Fe–REE deposit, Irkutsk district, Russia. It occurs in direct association with barite, biraite-(Ce), niobium-rich chevkinite-(Ce), fergusonite-(Nd), ancylite-(Ce) and ancylite-(La), daqingshanite-(Ce) and daqingshanite-(La), bastnasite-(Ce), hydroxylbastnasite-(Ce), carbocernaite, monazite-(Ce), talc, humite, thorite, pyrite, and pyrrhotite in carbonate veins composed of aragonite, strontianite, calcite, dolomite, and cordylite-(Ce). Cordylite-(La) forms as colorless, honey-yellow, or pinkish yellow, irregularly-shaped, tabular, or short-prismatic hexagonal crystals up to about 3 mm across. The only forms observed are {1010} and {0001} and crystals have perfect cleavage on {0001}. Crystals have a greasy to vitreous luster, a brittle tenacity, a conchoidal to uneven fracture, and a hardness of 4 on the Mohs scale. Crystals are uniaxial (−), ɛ = 1.573–1.574, and ω = 1.749–1.751. The empirical formula for two different crystals gave: (Na1.24Ca0.78)∑2.02Ba2.10[(La1.54Ce1.31Nd0.17Pr0.04)∑3.06Sr0.89]∑3.95(C1.01O3)8(F1.78OH0.05)∑1.83 and(Na1.23Ca0.79)∑2.02Ba1.98[(La1.43Ce1.33Nd0.25Pr0.10)∑3.11Sr0.94]∑4.05(C1.01O3)8(F1.51OH0.38)∑1.89. The crystal structure, solved on the same two crystals ( R 1 = 0.0246 and 0.0205) gave the unit cell parameters in P 63/ mcc: a = 5.1182(5) and c = 23.1785(16) A and V = 525.84(16) A3 and a = 5.1196(3) and c = 23.1784(16) A and V = 525.13(5) A3 with Z = 1, and confirms that the mineral is isostructural with cordylite-(Ce). We also discuss new heterovalent substitution mechanisms found in the cordylite group minerals and the effect they have during the formation of crystals.
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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 | 0.002 | 0.001 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 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".