Ferro-fluoro-edenite, a new amphibole endmember from Vulcano Island (Sicily, Italy)
Bibliographic record
Abstract
ABSTRACT Ferro-fluoro-edenite, ideally NaCa2Fe2+5(Si7Al)O22F2, was found as prismatic crystals up to 1.00 mm inside cavities in ejecta of the 1873 eruption at La Fossa crater, Vulcano Island, Aeolian Archipelago, Sicily, Italy. It is associated with quartz, magnetite, and vonsenite. Crystals are dark brown to black, transparent or semitransparent with vitreous luster, and non fluorescent. The Mohs hardness is 5–6. Cleavage is fair on {110} and fracture is uneven. Density (calc.) is 3.358 g cm–3 using the empirical formula and single-crystal cell data. The mineral is biaxial negative, α = 1.629(2), β = 1.659(2), γ = 1.667(2), 2V (calc.) = –53.8°, Y = b. Dispersion is weak to very weak, r < v, pleochroism not visible. Ferro-fluoro-edenite is monoclinic, space group C2/m, a = 9.9132(10), b = 18.1736(19), c = 5.2943(6) Å, β = 104.85(1)°, V = 922.0(2) Å3, Z = 2. The strongest X-ray diffraction peaks in the powder pattern are [d(I, hkl)]: 8.54(100, 1 1 0), 4.506(16, 0 4 0), 3.154(52, 3 1 0), 2.833(43, 3 3 0), 2.057(14, 2 0 2), 1.910(12, 5 1 0), 1.662(15, 4 6 1). The FTIR spectrum shows a broad band at about 950 cm–1 and no bands in the OH stretching region. The structure refinement led to a final R = 0.0210 for 1444 observed reflections with I > 2σ(I) and allowed cation site assignment and ordering. Microprobe analysis gave the following empirical formula calculated on the basis of 24 (O + F + Cl) apfu: (Na0.69K0.23□0.08)(Ca1.69Mg0.16Mn0.10Na0.05)Σ2(Fe2+2.86Mg2.04Ti0.10)Σ5(Si6.93Al1.05Ti0.02)Σ8O22(F1.89Cl0.09OH0.02)Σ2.
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How this classification was reachedexpand
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 | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.012 | 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 teacher head, 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".