FERROERICSSONITE, THE Fe2+ ANALOGUE OF ERICSSONITE, FROM EASTERN FRESNO COUNTY, CALIFORNIA, U.S.A.
Bibliographic record
Abstract
Ferroericssonite, ideally BaFe 2+ 2 Fe 3+ (Si 2 O 7 )O(OH), is a new mineral species found at both the Esquire #7 and #8 claims, situated along Big Creek in eastern Fresno County, and also at Trumbull Peak in Mariposa County, California, U.S.A. The mineral is the Fe 2+ analogue of ericssonite and is named accordingly. Ferroericssonite crystallized very late in a sequence of minerals resulting from fluids interacting with a quartz−sanbornite vein along its margin with the country rock. It is closely associated with anandite, bazirite, celsian, devitoite, quartz and titantaramellite. The crystals occur in dark reddish brown foliated masses of irregular, undulating striated blades up to several mm in length, flattened on {100} and elongate and striated parallel to [001]. The mineral is transparent and has a brown streak, a vitreous luster, a Mohs hardness of approximately 4½, and two cleavages: {100} perfect and {011} good. It is brittle with an irregular fracture. The calculated densities are 4.445 and 4.413 g/cm 3 on the basis of the empirical formulas for Esquire #7 and Esquire #8 material, respectively. It is optically biaxial (+), α 1.827(3), β 1.845(3), γ 1.920(6) (white light); 2 V meas = 63(2)°; 2 V calc = 63.0°; parallel dispersion, r v ; orientation: X = b , Y ≈ c , Z ≈ a ; pleochroic: brown, Z > X > Y . Electron-microprobe analyses of Esquire #7 and Esquire #8 material provided: BaO 30.11, 29.76, MgO 0.21, 0.10, MnO 1.19, 0.79, FeO 26.01, 26.24, Fe 2 O 3 15.30, 15.35, Al 2 O 3 0.02, 0.04, SiO 2 22.89, 23.34, F 0.09, 0.05, Cl 1.29, 0.88, H 2 O 1.33, 1.42, F + Cl≡ O −0.33, −0.22, total 98.11, 97.75 wt%, with FeO and Fe 2 O 3 assignments and H 2 O based on the structure. The empirical formulas for Esquire #7 and Esquire #8 material, based on Mg + Fe + Mn + Si = 5 apfu , are Ba 1.02 (Fe 2+ 1.89 Mn 2+ 0.09 Mg 0.03 ) ∑2.01 Fe 3+ 1.00 (Si 1.99 O 7 )O[(OH) 0.77 O 0.02 Cl 0.19 F 0.02 ] ∑1 and Ba 1.01 (Fe 2+ 1.90 Mn 2+ 0.06 Mg 0.01 ) ∑1.97 Fe 3+ 1.00 (Si 2.02 O 7 )O[(OH) 0.82 O 0.04 Cl 0.13 F 0.01 ] ∑1 , respectively. Ferroericssonite is monoclinic, C 2/ m , a 20.3459(10), b 7.0119(3), c 5.3879(4) A, β 94.874(7)°, V 765.89(7) A 3 and Z = 4. The strongest five lines in the X-ray powder-diffraction pattern [ d obs in A( I )( hkl )] are: 3.708(42)(311), 3.506(81)(311, 510, 020), 2.880(42)(420), 2.788(100)(221) and 2.663(83)( 202, 710). The crystal-structure determination ( R 1 = 3.56% for 885 F o > 4σ F ) shows the mineral to be a heterophyllosilicate with a Fe 2+ trioctahedral (O) sheet flanked on either side by heterophyllosilicate (H) layers, forming a HOH composite sheet. The heterophyllosilicate layers are composed of Si 2 O 7 groups linked by Fe 3+ square pyramids in a configuration referred to as a TS (Ti silicate) block, although five-coordinated Fe 3+ takes the place of Ti 4+ . The region between the composite sheets is occupied by Ba 2+ . Ferroericssonite is a member of the lamprophyllite group.
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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 | 0.002 | 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) | 0.004 | 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".