Yarzhemskiite, K[B<sub>5</sub>O<sub>7</sub>(OH)<sub>2</sub>]⋅H<sub>2</sub>O, a new mineral from the Chelkar salt dome, Western Kazakhstan
Bibliographic record
Abstract
Abstract The new mineral yarzhemskiite, K[B5O7(OH)2]⋅H2O, was found in a halite–sylvite evaporite rock at the Chelkar salt dome, Western Kazakhstan Region, Kazakhstan. It is also associated with carnallite, polyhalite, gypsum, strontioginorite, satimolite and quartz. Yarzhemskiite occurs as separate thick tabular, short prismatic or equant crystals up to 0.5 mm × 0.7 mm × 1 mm and grains having irregular outlines up to 1 mm × 1.5 mm × 2 mm. The mineral is transparent, colourless, with vitreous lustre. It is brittle, the Mohs’ hardness is ca 2½. Cleavage is perfect on {100}. Dmeas is 2.13(1) and Dcalc is 2.112 g cm–3. Yarzhemskiite is optically biaxial (+), α = 1.484(2), β = 1.508(2), γ = 1.546(2), 2Vmeas = 75(10)° and 2Vcalc = 80°. Chemical composition (wt.%, electron microprobe, H2O was calculated by stoichiometry) is: Na2O 0.01, K2O 17.84, CaO 0.07, B2O3 67.21, H2Ocalc 13.91, total 99.04. The empirical formula based on 10 O atoms per formula unit is K0.98B5.005O7(OH)2⋅H2O. Yarzhemskiite is monoclinic, P21/c, a = 9.47340(18), b = 7.52030(16), c = 11.4205(2) Å, β = 97.3002(17)°, V = 807.03(3) Å3 and Z = 4. The strongest reflections of the powder XRD pattern [d,Å(I,%)(hkl)] are: 9.39(86)(100), 4.696(41)(200), 3.296(18)( $\bar{1}$ 13), 3.130(19)(022, 300), 2.935(42)(220), 2.898(100)( $\bar{3}$ 02, $\bar{2}$ 21, 310), 2.832(56)(004) and 1.867(18)( $\bar{2}$ 25). The crystal structure was solved based on single-crystal X-ray diffraction data, R1 = 3.36%. The structure contains infinite chains built by boron-centred polyhedra. The basic structural unit of the chain is a double ring B5O7(OH)2 consisting of one BO4 tetrahedron and four BO3 triangles. K+ cations centre ten-fold polyhedra which form, together with the borate chains [B5O7(OH)2]–∝, layers linked with each other only via H bonds. The mineral is named in honour of the Russian geologist, petrologist and mineralogist Yakov Yakovlevich Yarzhemskii (1901–?), a specialist in petrology of evaporite rocks and mineralogy and genesis of boron deposits related to evaporites.
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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 | 0.000 |
| 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) | 0.001 | 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".