BURGESSITE, Co2 (H2O)4 [AsO3(OH)]2 (H2O), A NEW ARSENATE MINERAL SPECIES FROM THE KEELEY MINE, SOUTH LORRAIN TOWNSHIP, ONTARIO, CANADA
Bibliographic record
Abstract
Burgessite, Co 2 (H 2 O) 4 [AsO 3 (OH)] 2 (H 2 O), is a new mineral species of supergene origin from the Keeley mine, South Lorrain Township, Timiskaming District, Ontario, Canada. Burgessite forms rosettes up to 0.8 mm across consisting of prismatic crystals up to 0.1 mm long, elongate along a , with the following forms: {011} >> { h 0 l }, and no observable twinning. It is associated with primary skutterudite, cobaltite and bismuth, and supergene arsenolite, bismutoferrite and erythrite. Burgessite is transparent, purplish pink with a slight brown tint, and has a colorless to pale pink streak and a vitreous luster; it does not fluoresce under ultraviolet light. It exhibits two cleavages, {010} good and {001} fair. The Mohs hardness is ~3; burgessite is brittle with a hackly fracture, and has measured and calculated densities of 2.93(2) and 2.94 g/cm 3 , respectively. Burgessite is biaxial positive with α 1.596, β 1.604, γ 1.628, all ±0.002, with a 2 V obs of 70(2)° and 2 V calc = 61°. It is nonpleochroic, with an optic orientation X = b , Y ∧ c = 29° (in β obtuse), Z ∧ a = 20° (in β acute). Burgessite is monoclinic, space group P 2 1 /n , a 4.7058(12), b 9.299(3), c 12.738(4) A, β 98.933(8)°, V 550.6(5) A 3 , Z = 2, a:b:c = 0.5061:1:1.3698. The strongest seven lines in the X-ray powder-diffraction pattern [ d in A(I)( hkl )] are: 7.446(100)(011), 6.267(44)(002), 3.725(29)(022), 3.260(25)(121), 2.998(31)(031), 2.970(21)(014) and 2.596(23)(024). A chemical analysis with an electron microprobe gave As 2 O 5 47.91, P 2 O 5 0.03, CoO 27.31, NiO 3.52, ZnO 0.04, CaO 0.18, SO 3 0.13, H 2 O (calc.) 22.65, for a sum of 101.77 wt.%; the valence states of As and Co, and the amount of H 2 O, were determined by crystal-structure analysis. The resulting empirical formula on the basis of 13 (O, OH, H 2 O) anions is (Co 1.75 Ni 0.23 Ca 0.02 ) ∑2.00 (AsO 3 OH) ∑2.00 (H 2 O) 5 . The crystal structure of burgessite consists of chains of the form [Co 2 (H 2 O) 4 (As 5+ O 3 (OH)) 2 ] that extend in the a direction and are linked by hydrogen bonds, and is closely related to that of erythrite.
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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 | 0.001 | 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) | 0.002 | 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".