KOTTENHEIMITE, Ca3Si(OH)6(SO4)2{middle dot}12H2O, A NEW MEMBER OF THE ETTRINGITE GROUP FROM THE EIFEL AREA, GERMANY
Bibliographic record
Abstract
The new ettringite-group mineral kottenheimite was found at Bellerberg, near Kottenheim, Eastern Eifel area, Rhineland- Palatinate (Rheinland-Pfalz), Germany, and named for the type locality. Associated minerals are wollastonite, clinochlore, ellestadite, melilite, cuspidine, and earlier formed sanidine, clinopyroxene, and magnetite. Kottenheimite forms white radiated and random aggregates of hair-like subparallel clusters of minute crystals. The Mohs’ hardness is 2–2.5; D meas = 1.92(2) g/cm 3 , D calc = 1.926 g/cm 3 . The new mineral is uniaxial (−), ω = 1.490(2), ɛ = 1.477(2). The IR spectrum of kottenheimite is in accordance with the chemical composition and contains absorption bands in the range 3300–3700 cm −1 (O–H-stretching vibrations), at 1650 and 1683 cm −1 (bending vibrations of H 2 O molecules), 1158, 1086, and 987 cm −1 (showing the presence of distorted SO 4 2− groups), 752 and 725 cm −1 (corresponding to Si–O stretching vibrations of Si(OH) 6 octahedra). The chemical composition is (electron microprobe, mean of 6 analyses, wt.%; H 2 O and CO 2 determined by gas chromatography): CaO 26.04, MgO 0.20, FeO 0.19, Al 2 O 3 0.25, SiO 2 8.95, SO 3 24.26, CO 2 0.58, H 2 O 41.30; total 101.77. The empirical formula calculated on the basis of 26 anions is Ca 3.015 Mg 0.03 Fe 0.02 Al 0.03 Si 0.97 (OH) 5.94 (SO 4 ) 1.97 (CO 3 ) 0.09 ·11.91H 2 O. The simplified formula is Ca 3 Si(OH) 6 (SO 4 ) 2 ·12H 2 O. The crystal structure was refined by the Rietveld method ( R p = 0.0487, R wp = 0.0623, R B = 0.087) based on the structural model of carraraite, Ca 3 Ge(SO 4 ,CO 3 ) 2 (OH) 6 ·12H 2 O. The new mineral is hexagonal, space group P 6 3 / m , a = 11.1548(3), c = 10.5702(3) A, V = 1139.04(5) A 3 , and Z = 2. The strongest lines of the powder diffraction pattern [ d in A ( I ) ( hkl )] are: 9.72 (100) (100), 5.590 (60) (110), 4.645 (26) (102), 3.840 (54) (112), 2.751 (34) (302), 2.536 (27) (213), 2.185 (30) (223). The channels in the crystal structure of kottenheimite are only filled by sulfate anions and water molecules. Type material is deposited in the collections of the Fersman Mineralogical Museum of the Russian Academy of Sciences, Moscow, Russia, registration number 4102/1.
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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".