Heyerdahlite, Na<sub>3</sub>Mn<sub>7</sub>Ti<sub>2</sub>(Si<sub>4</sub>O<sub>12</sub>)<sub>2</sub>O<sub>2</sub>(OH)<sub>4</sub>F(H<sub>2</sub>O)<sub>2</sub>, a new mineral of the astrophyllite supergroup from the Larvik Plutonic complex, Norway: Description and crystal structure
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Bibliographic record
Abstract
ABSTRACT Heyerdahlite, ideally Na 3 Mn 7 Ti 2 (Si 4 O 12 ) 2 O 2 (OH) 4 F(H 2 O) 2 , is a new astrophyllite-supergroup mineral from the Larvik Plutonic complex, Norway. Heyerdahlite was found in a nepheline-syenite pegmatite with albite, aegirine, hastingsite/magnesio-hastingsite, kupletskite, lorenzenite and pyrophanite. Heyerdahlite is colourless to pale brown, transparent and has a vitreous lustre. Mohs hardness is 3, D calc. = 3.245 g/cm 3 . Heyerdahlite is biaxial (+), α = 1.694(2), β = 1.710(5), γ = 1.730(5), 2V meas. = 80(4)° and 2V calc. = 84.5°. Cleavage is perfect parallel to {001}. The empirical formula based on 32.18 (O + F) apfu is (Na 1.18 K 0.68 Rb 0.12 Cs 0.01 Pb 0.01 ) Σ2 Na 1.00 (Mn 6.29 Zn 0.23 Mg 0.07 Zr 0.04 ${\rm Fe}_{{\rm 0}{\rm. 03}}^{{\rm 2 +}} $ Ca 0.01 Na 0.34 ) Σ7.01 (Ti 1.78 Nb 0.17 Mg 0.03 Zr 0.02 ) Σ2 (Si 8.03 O 24 )O 2 [(OH) 3.92 F 0.08 ] Σ4 F 1.00 [(H 2 O) 1.18 □ 0.82 ] Σ2 , for Z = 1. Heyerdahlite is triclinic, space group P $\bar 1$ , a = 5.392(2), b = 11.968(4), c = 11.868(4) Å, α = 112.743(8), β = 94.816(7), γ = 103.037(8)° and V = 675.6(7) Å 3 . The crystal structure was refined to R 1 = 4.44% for 3577 unique ( F o > 4σ F ) reflections. In the crystal structure of heyerdahlite, there are four [4] T sites occupied by Si. The [6] D site is occupied mainly by Ti. The T 4 O 12 astrophyllite ribbons composed of SiO 4 tetrahedra and D octahedra constitute the H (Heteropolyhedral) sheet. In the O (Octahedral) sheet, there are four Mn-dominant [6] M (1–4) sites. Two H sheets and one central O sheet form the HOH block, and adjacent HOH blocks link via a common ${\rm X}_{\rm D}^{\rm P} $ anion of the two D octahedra. In the I (Intermediate) block between HOH blocks, there are two interstitial cation sites, A and B , and a W A site, partly occupied by H 2 O. The A site splits into two sites, [12] A (1) and [6] A (2), partly occupied by K and Na, respectively, with A(1)–A(2) = 0.754 Å. The aggregate content of the A site is ideally Na 2 apfu. The [10] B site is occupied by Na. The W A site is ideally occupied by (H 2 O) 2 pfu. The mineral is named after the Norwegian explorer Thor Heyerdahl (1914–2002), who was born in Larvik.
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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 | 0.006 | 0.004 |
| Meta-epidemiology (narrow) | 0.012 | 0.010 |
| Meta-epidemiology (broad) | 0.012 | 0.006 |
| Bibliometrics | 0.003 | 0.006 |
| Science and technology studies | 0.009 | 0.010 |
| Scholarly communication | 0.008 | 0.007 |
| Open science | 0.012 | 0.009 |
| Research integrity | 0.007 | 0.010 |
| Insufficient payload (model declined to judge) | 0.000 | 0.002 |
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 it