THERMESSAITE, K2[AlF3 SO4], A NEW INO-ALUMINOFLUORIDE-SULFATE FROM LA FOSSA CRATER, VULCANO, AEOLIAN ISLANDS, ITALY
Bibliographic record
Abstract
Thermessaite, ideally K 2 [AlF 3 |SO 4 ], is a new inoaluminofluoride-sulfate found in active medium- to high-temperature fumaroles (300–350°C) at the rim of La Fossa crater, Vulcano Island, Aeolian archipelago, Sicily, Italy. The mineral occurs as sharp translucent crystals up to 0.25 mm in an altered pyroclastic breccia, together with alunite, sassolite, anhydrite and metavoltine. It is orthorhombic ( mmm ), space group Pbcn , with a 10.810(2), b 8.336(2), c 6.822(1) A, V 614.8(2) A 3 , Z = 4; the crystal habit is prismatic, with {110} and the pinacoid {100} as the dominant forms, terminated by minor faces of the bipyramid {111}.The mineral is colorless to white; the streak is white, the luster, vitreous, and the tenacity, brittle. It is nonfluorescent. Cleavage and fracture were not observed. The calculated density is 2.790 g/cm 3 , the observed density is 2.77(2) g/cm 3 , and the mean index of refraction is 1.445. The chemical analysis leads to the empirical formula K 2.02 [Al 1.05 F 3.17 S 0.94 O 3.83 ], corresponding to the ideal formula K 2 [AlF 3 |SO 4 ]. The structure was refined to a final R = 0.0286 for 685 observed reflections [ I > 2σ ( I )]. It contains chains of corner-sharing AlF 4 O 2 octahedra running along [001]; these octahedra share two vertices with SO 4 tetrahedra [Al–F distances 1.752(1) × 2 and 1.844(1) A × 2, and Al–O 1.906(1) A × 2]; this structural motif is new for aluminofluoride minerals. The K + ions are surrounded by five oxygen atoms [ 2.642(2)–3.247(2) A] and by four fluorine atoms [ 2.682(2)–2.926(2) A]. The strongest six lines in the X-ray powder-diffraction pattern [ d obs in A( I ) hkl ] are: 2.983(100)(311), 2.702(82)(130), 6.631(70) (110), 1.712(58)(530), 2.208(30)(330) and 3.317(28)(310). The mineral is named after Thermessa (θeρμeσσα), an ancient Greek name of the Island of Vulcano meaning “the warm island”. Both the mineral and the mineral name have been approved by the IMA Commission on New Minerals, Nomenclature and Classification (No. 2007–030).
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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 | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 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".