Lumsdenite, NaCa3Mg2(As3+V4+2V5+10As5+6O51)·45H2O, a new polyoxometalate mineral from the Packrat mine, Mesa County, Colorado, USA
Bibliographic record
Abstract
ABSTRACT Lumsdenite (IMA 2018–092), ideally NaCa3Mg2(As3+V4+2V5+10As5+6O51)·45H2O, is a rare new polyoxometalate mineral from the Packrat mine, Gateway district, Mesa County, Colorado, USA. Crystals of lumsdenite occur as blades up to 0.2 mm in length, commonly growing in sprays. The crystals are dark green blue, with a green-blue streak. The mineral occurs on asphaltum, associated with montroseite- and corvusite-bearing sandstone. Other secondary minerals found in close association with lumsdenite are gypsum, huemulite, rösslerite, and at least two other potentially new minerals. Lumsdenite is optically biaxial (–), with α 1.617(2), β 1.651(5), and γ 1.675(5) in white light. The pleochroism scheme for lumsdenite is X = greenish yellow, Y = dark greenish blue, Z = greenish blue; X << Z < Y. The mineral is triclinic, , with a 10.3490(5), b 17.6263(9), c 23.2556(16) Å, α 82.208(6), β 88.351(6), γ 81.702(6)°, V 4158.8(4) Å3, and Z = 2. The strongest four powder diffraction lines for lumsdenite are [dobs Å(I)(hkl)]: , 14.86(80)(011), 17.30(44)(010), and 10.22(32)(100). The atomic arrangement of lumsdenite contains the novel polyoxometalate heteropolyanion [As3+V4+,5+12As5+6O51] structural unit in lumsdenite, [As3+V4+25+10As5+6O51]11−, which has previously been found in four other minerals from the Packrat mine. The charge of the structural unit is balanced by the charge of the [NaCa3Mg2(H2O)31·14H2O]11+ interstitial complex. The name lumsdenite is for the location of the mine at the head of Lumsden Canyon.
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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 | 0.000 | 0.000 |
| Science and technology studies | 0.001 | 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".