CHUBAROVITE, KZn<sub>2</sub>(BO<sub>3</sub>)Cl<sub>2</sub>, A NEW MINERAL SPECIES FROM THE TOLBACHIK VOLCANO, KAMCHATKA, RUSSIA
Bibliographic record
Abstract
The new mineral chubarovite, KZn 2 (BO 3 )Cl 2 , was found in the sublimates of active fumaroles at the Second and First scoria cones of the Northern Breakthrough of the Great Tolbachik Fissure Eruption, Tolbachik volcano, Kamchatka, Russia. At the Second scoria cone it occurs in the Arsenatnaya fumarole (the holotype) with fluoborite, krasheninnikovite, sylvite, halite, langbeinite, aphthitalite, orthoclase, fluorophlogopite, hematite, and tenorite. At the First scoria cone, chubarovite is closely associated with sellaite, fluorite, anhydrite, halite, cotunnite, challacolloite, sofiite, and flinteite. Chubarovite forms hexagonal or trigonal lamellar to tabular crystals up to 1.5 mm across and up to 0.5 mm thick, with aggregates and crystal crusts up to 1 cm across. The major crystal form is {001}, and lateral faces are {101}, {102}, {103}, {100}, and {110}; twins of two types are observed. Chubarovite is transparent, colorless, with vitreous luster. It is flexible but not elastic. The Mohs hardness is ca . 2. Cleavage is (001) perfect, mica-like. D (meas.) is 2.68(2), D (calc.) is 2.716 g cm –3 . Chubarovite is optically uniaxial (–), with ω 1.541(2), e 1.539(2). The infrared spectrum is given. Chemical data (wt.%, determined by electron-microprobe, boron by ICP OES) are: K 2 O 16.48, Rb 2 O 0.46, ZnO 53.96, B 2 O 3 10.98, Cl 24.48, –O=Cl 2 –5.53, total 100.83. The empirical formula, based on 5 (O+Cl) apfu , is: (K 1.05 Rb 0.01 ) Σ 1.06 Zn 2.00 B 0.95 O 2.92 Cl 2.08 . Chubarovite is trigonal, R 32, a 4.9429(4), c 26.348(2) A, V 557.50(8) A 3 , and Z = 3. The strongest reflections of the powder X-ray diffraction pattern [ d ,A( I )( hkl )] are: 8.79(100)(003), 4.394(43)(006), 4.225(25)(101), 4.074(91)(012), 3.590(90)(104), 3.324(30)(015), 2.470(67)(110), and 2.245(25)(1.0.10). Chubarovite has a novel structure type. Its crystal structure, solved from single-crystal X-ray diffraction data ( R = 0.020), is composed of layers of two types with an alternation along [001]. The anionic {Zn 2 (BO 3 )Cl 2 } – layer consists of flat triangular BO 3 groups sharing all O vertices with bases of ZnO 3 Cl tetrahedra. Each Cl atom is shared between one Zn-centered tetrahedron and three edge-connected KCl 6 octahedra belonging to the cationic layer formed by K + cations. The mineral is named in honor of the Russian mineralogist and physicist Valeriy M. Chubarov (born 1948).
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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 | 0.001 | 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".