Dukeite, Bi <sub>24</sub> <sup>3+</sup> Cr <sub>8</sub> <sup>6+</sup> O <sub>57</sub> (OH) <sub>6</sub> (H <sub>2</sub> O) <sub>3</sub> , a new mineral from Brejaúba, Minas Gerais, Brazil: Description and crystal structure
Why this work is in the frame
A frame that forgets how it found something cannot be audited. These are the routes that admitted this work.
Bibliographic record
Abstract
Dukeite, Bi3+24Cr86+O57(OH)6(H2O)3, space group P31c, a = 15.067(3), c = 15.293(4) Å, V = 3007(1) Å3, Z = 2, is a new mineral found on a museum specimen labeled as originating from the São José Mine, Brejaúba, Minas Gerais, Brazil. The strongest seven lines of the X-ray powder-diffraction pattern [d in Å (I) (hkl)] are: 7.650 (50) (002), 3.812 (40) (004), 3.382 (100) (222), 2.681 (70) (224), 2.175 (40) (600), 2.106 (40) (226), 1.701 (50) (228). It occurs as groupings of tightly bound 1 × 0.3 mm2 sized sheaves that are associated with pucherite, schumacherite, bismutite, and hechtsbergite. Individual acicular crystals do not exceed 100 μm in length by 1-2 μm in width. Crystals are yellow inclining to a dirty yellow-brown, possess a bright yellow streak, are transparent, brittle, resinous, and do not fluoresce under ultraviolet light. The estimated Mohs hardness is between 3 and 4, the calculated density (for the empirical formula) is 7.171 g/cm3, and the mineral is slowly soluble in concentrated HCl. Electron-microprobe analyses yielded Bi2O3 85.06, CrO3 11.65, V2O5 0.59, H2O (calc.) [1.67], total [98.97] wt%. The empirical formula, derived from the crystalstructure analysis and electron-microprobe analyses, is Bi3+23.95(Cr6+7.64V5+0.43)Σ8.07O56.84(OH)6.16⋅3.01 H2O, based on O = 66. In reflected plane-polarized light in air it is gray to purplish gray with strong yellow internal reflections. Bireflectance is very weak. Measured reflectance values, in air and in oil, are tabulated: indices of refraction calculated from these at 590 nm are 2.33 and 2.37. The name honors Duke University, Durham, North Carolina, in whose collection the mineral was found and also recognizes the contribution of the Duke family to the advancement of scientific knowledge.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
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 | 0.002 | 0.002 |
| Meta-epidemiology (narrow) | 0.007 | 0.008 |
| Meta-epidemiology (broad) | 0.007 | 0.003 |
| Bibliometrics | 0.004 | 0.008 |
| Science and technology studies | 0.003 | 0.009 |
| Scholarly communication | 0.004 | 0.006 |
| Open science | 0.005 | 0.002 |
| Research integrity | 0.003 | 0.005 |
| Insufficient payload (model declined to judge) | 0.001 | 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