SODIC-FERRI-FERROPEDRIZITE AND FERRI-CLINOFERROHOLMQUISTITE: MINERAL DATA AND DEGREE OF ORDER OF THE A-SITE CATIONS IN Li-RICH AMPHIBOLES
Bibliographic record
Abstract
A systematic examination of metamorphic episyenites in the Pedriza Massif, Sierra de Guadarrama, Spain, allowed detection of two more distinct Li-rich C 2/ m amphibole species. They can be related to previously described species via the homovalent exchanges M 1(Fe2+Mg−1) and M 2(Fe3+Al−1), and represent the compositions richest in Fe in this compositional space. The ideal formula of ferri-clinoferroholmquistite is A □ B Li2 C (Fe3+ 2Fe2+ 3) T Si8 O22 X (OH)2, and that of sodic-ferri-ferropedrizite is A Na B Li2 C (Fe3+ 2Fe2+ 2Li) T Si8 O22 X (OH)2, with Z = 2. Holotype ferri-clinoferroholmquistite (IMA–CNMMN 2001–066), A (Na0.28K0.00)∑0.28 B (Li1.90Na0.08Ca0.02)∑2.00 C (Fe3+ 1.68Fe2+ 1.55Mg1.06Li0.28Al0.26Ti0.01Mn2+ 0.14Zn0.02)∑5.00 T Si8.00 O22O3(OH1.79F0.24)∑2.03, has a 9.462(6), b 17.898(9), c 5.302(3) A, β 101.88(4)°, V 878.6(2) A3. Holotype sodic-ferri-ferropedrizite (IMA–CNMMN 2001– 068), A (Na0.53K0.03)∑0.56 B (Li1.82Na0.15Ca0.03)∑2.00 C (Fe3+ 1.55Fe2+ 1.49Mg0.95Li0.58Al0.21Ti0.13 Mn2+ 0.07Zn0.01)∑4.99 T Si8.00 O22 X (OH1.45F0.52)∑1.97, has a 9.496(4), b 17.883(8), c 5.297(2) A, β 102.06(3)°, V 879.6(2) A3. Sodic-ferri-ferropedrizite and ferri-clinoferroholmquistite are both black, with a vitreous luster. They have a gray streak and do not show fluorescence under long-and short-wave ultraviolet light; they are brittle with an uneven fracture, and have the characteristic {110} cleavage of monoclinic amphiboles. The calculated values of density are 3.23 and 3.24 g/cm3, and the calculated mean indices of refraction are 1.708 and 1.710, respectively. The shape of the electron density at the A sites changes as a function of the B Li and C Li contents, suggesting that cation ordering is strongly affected by local bond-valence requirements. This feature is confirmed by systematic bond-valence – bond-strength calculations, which support the sequence ( M 4′Li–O3F– Am Na) > ( M 4′Li–O3OH– Am Na) of preferred local configurations.
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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 | 0.000 | 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) | 0.001 | 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".