Folvikite, Sb<sup>5+</sup>Mn<sup>3+</sup>(Mg,Mn<sup>2+</sup>)<sub>10</sub>O<sub>8</sub>(BO<sub>3</sub>)<sub>4</sub>, a new oxyborate mineral from the Kitteln mine, Nordmark ore district, Värmland, Sweden: description and crystal structure
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Bibliographic record
Abstract
ABSTRACT Folvikite, Sb 5+ Mn 3+ (Mg,Mn 2+ ) 10 O 8 (BO 3 ) 4 , is a new oxyborate mineral from the Kitteln mine, Värmland, Sweden, where it occurs as a primary skarn mineral embedded in calcite. It forms striated prismatic crystals up to 0.3 mm, and is black to dark reddish-brown with submetallic lustre and a reddish-brown streak. It is brittle, has a Mohs hardness of 6, and the calculated density is 4.14 g/cm 3 . Folvikite is biaxial with indeterminate optic sign due to pervasive twinning. The optic axial angle is 68.9(4)°. Refractive indices were not measured; the calculated mean refractive index is 1.85. Strong pleochroism was observed in plane-polarized light: AB = brown (intermediate), OB = dark brown (maximum) and ON = honey brown (minimum). Folvikite is monoclinic, space group P 2, a = 5.3767(10), b = 6.2108(10), c = 10.9389(18) Å, β = 94.399(9)°, V = 364.22(16) Å 3 and Z = 1. Chemical analysis by electron microprobe gave Sb 2 O 5 18.15, MgO 24.11, MnO 29.73, Mn 2 O 3 11.62, Al 2 O 3 0.27, Fe 2 O 3 0.45, B 2 O 3 15.27, sum 99.60 wt.%. The B 2 O 3 content was assigned as B = 4 apfu and the Mn 2 O 3 / (MnO + Mn 2 O 3 ) ratio was determined from the crystal structure. The empirical formula was normalized on the basis of 20 anions pfu: (Sb 5+ 1.02 Mn 3+ 1.34 Al 0.05 Fe 3+ 0.05 Mg 5.46 Mn 2+ 3.82 □ 0.26 ) Σ12 O 8 (BO 3 ) 4 . A simplified formula may be written as Sb 5+ Mn 3+ (Mg,Mn 2+ ) 10 O 8 (BO 3 ) 4 with Z = 1. The crystal structure was solved by direct methods and refined to an R 1 index of 4.1%. Folvikite is a member of the (3 Å) zigzag wallpaper-borate structures in which chains of edge-sharing octahedra extend along the c axis and are cross-linked by BO 3 groups. There are five X sites partly occupied by Mn 2+ > Mg, one octahedrally coordinated M -site occupied by Sb 5+ > Mg, two M sites occupied by Mg ≥ Mn > Sb 5+ , two M sites occupied by Mn 3+ > Mn 2+ , two M sites occupied by Mg > Mn 2+ , and one M -site occupied by Mg > □; plus two [3]-coordinated B sites occupied by B. As with the other zigzag borates, the polyhedra are arranged in F-walls, C-walls and S-columns.
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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 | 0.001 | 0.002 |
| Meta-epidemiology (narrow) | 0.003 | 0.002 |
| Meta-epidemiology (broad) | 0.003 | 0.001 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.003 | 0.003 |
| Scholarly communication | 0.005 | 0.003 |
| Open science | 0.003 | 0.002 |
| Research integrity | 0.002 | 0.002 |
| Insufficient payload (model declined to judge) | 0.001 | 0.001 |
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