Classification of Bobtraillite |
| IMA status: | Approved 2001 |
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| Strunz 8th edition ID: | 8/E.0-
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| Nickel-Strunz 10th (pending) edition ID: | 9.CA.30
9 : SILICATES (Germanates) C : Cyclosilicates A : [Si3O9]6- 3-membered single rings (dreier-Einfachringe), without insular complex anions |
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| mindat.org URL: | http://www.mindat.org/min-27406.html Please feel free to link to this page. |
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Type Occurrence of Bobtraillite |
| Type Locality: | Poudrette quarry (Demix quarry; Uni-Mix quarry; Desourdy quarry), Mont Saint-Hilaire, Rouville RCM, Montérégie, Québec, Canada |
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| General Appearance of Type Material: | generally isolated single crystals with a maximum length of 2 mm or simple parallel intergrowths with two or three members, rarely in small (<0.1 mm) rosettes |
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| Geological Setting of type material: | The mineral is found in igneous breccias and nepheline syenite pegmatites. It is paragenetically late, arising from unusual, hydrous fluids enriched in B, Sr, Na and Zr. |
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| Associated Minerals at type locality: | |
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Physical Properties of Bobtraillite |
| Lustre: | Vitreous |
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| Diaphaneity (Transparency): | Transparent |
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| Colour: | grey to brown |
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| Streak: | white |
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| Hardness (Mohs): | 5½ |
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| Tenacity: | Brittle |
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| Cleavage: | None Observed |
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| Fracture: | Irregular/Uneven, Conchoidal |
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| Density (calculated): | 3.16 g/cm3 |
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Crystallography of Bobtraillite |
| Crystal System: | Trigonal |
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| Class (H-M): | 3m (3 2/m) - Hexagonal Scalenohedral |
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| Space Group: | P3 1c {P3 1 2/c} |
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| Cell Parameters: | a = 19.72Å, c = 9.9788Å
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| Ratio: | a:c = 1 : 0.506 |
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| Unit Cell Volume: | V 3360.7 ų |
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| Z: | 1 |
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| Morphology: | Commonly blocky to prismatic, elongate along [001]
The structure of bobtraillite was refined to R = 3.49% and wR2 = 10.88% for 1575 reflections [Fo > 4σ(Fo)]: Isolated ZrO6 octahedra are linked by (Si3O9) rings to form a pinwheel-like motif similar to that found in wadeite. Additional (Si3O9) and [Si2BO7(OH)2] rings complete a two-dimensional, giant pinwheel motif along [001]. Bonding between three-membered rings and ZrO6 octahedra along [001] completes the structure in three dimensions. Channels along [001] are occupied by Na, H2O and Sr. |
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| X-Ray Powder Diffraction: | | d-spacing | | Intensity | | 2.752 | | (100) | | 3.13 | | (70) | | 3.96 | | (51) | | 3.76 | | (49) | | 6.46 | | (38) |
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| Comments: | Format: d (I) (hkl). Only the six strongest lines are given. |
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Optical Data of Bobtraillite |
| Type: | Uniaxial (+) |
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| RI values: | nω = 1.627 nε = 1.645 |
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| Maximum Birefringence: | δ = 0.018
 Chart shows birefringence interference colour range (at 30µm thickness) and does not take into account mineral colouration. |
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| Surface Relief: | Moderate |
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| Pleochroism: | Non-pleochroic |
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Chemical Properties of Bobtraillite |
| Formula: | | (Na,Ca) | | Sr | | (Zr,Y,Nb) | | [(Si | | O | | ) | | |(H | | BSi | | O | | ) | | ] · 12H | | O |
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| All elements listed in formula: | B, Ca, H, Na, Nb, O, Si, Sr, Y, Zr |
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| Analytical Data: | The values are averages of seven analyses on one crystal. The B2O3 and H2O contents were calculated. The empirical formula is based on the assumption that there are 156 oxygen atoms present per formula unit.
Na2O (5.62)
CaO (1.11)
SrO (17.76)
BaO (0.40)
B2O3 (3.38)
Y2O3 (1.15)
SiO2 (40.51)
ZrO2 (25.32)
HfO2 (0.48)
Nb2O5 (1.32)
H2O (5.25)
total (102.30) |
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| Empirical Formula: | | (Na | | Ca | | ) | | (Sr | | Ba | | ) | | (Zr | | Y | | Nb | | Hf | | ) | | Si | | B | | O | | (OH) | | · 12H | | O |
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| Common Impurities: | Ba,Hf |
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Relationship of Bobtraillite to other Species |
Related Minerals - Nickel-Strunz Grouping):
- + | |
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Other Names for Bobtraillite |
| Synonyms: | |
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| Other Languages: | |
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Other Information |
| Fluorescence in UV light: | none |
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| Health Warning: | No information on health risks for this material has been entered into the database. You should always treat mineral specimens with care. |
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References for Bobtraillite |
| Reference List: | A.M. McDonald & G.Y. Chao: "Bobtraillite, (Na,Ca)13Sr11(Zr,Y,Nb)14Si42B6O132(OH)12•12H2O, a new mineral species from Mont Saint-Hilaire, Quebec: description, structure determination and relationship to benitoite and wadeite", The Canadian Mineralogist 43:747-758 (2005) |
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Internet Links for Bobtraillite |
| Search Engines: |
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| External Links: | Look for Bobtraillite on WebmineralLook for Bobtraillite on Athena MineralogyLook for Bobtraillite on WikipediaLook for Bobtraillite on Mineralien AtlasRaman and XRD data at RRUFF projectAmerican Mineralogist Crystal Structure DatabaseSearch for Bobtraillite in the Natural History Museum (London) online catalogue |
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Localities for Bobtraillite |
The map shows a selection of localities that have latitude and longitude coordinates recorded. Click on the  symbol to view information about a locality.
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