Classification of Fluor-dravite |
| IMA status: | Approved 2010 |
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| Nickel-Strunz 10th (pending) edition ID: | 9.CK.05
9 : SILICATES (Germanates) C : Cyclosilicates K : [Si6O18]12- 6-membered single rings, with insular complex anions |
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| mindat.org URL: | http://www.mindat.org/min-39892.html Please feel free to link to this page. |
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Type Occurrence of Fluor-dravite |
| Type Locality: | Crabtree Mine (Big Crabtree Emerald Mine), Spruce Pine, Spruce Pine District, Mitchell Co., North Carolina, USA |
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| General Appearance of Type Material: | Isolated anhedral grains up to a few mm across. |
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| Place of Conservation of Type Material: | Smithsonian Institution, Washington, D.C., USA (catalogue number 121341). |
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| Geological Setting of type material: | At or near the boundary of a small body of granitic pegmatite with the surrounding country-rock. |
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| Associated Minerals at type locality: | |
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Physical Properties of Fluor-dravite |
| Lustre: | Vitreous |
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| Colour: | Blackish brown |
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| Streak: | Pale brown |
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| Hardness (Mohs): | 7 |
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| Tenacity: | Brittle |
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| Fracture: | Conchoidal |
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| Density (calculated): | 3.120 g/cm3 |
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Crystallography of Fluor-dravite |
| Crystal System: | Trigonal |
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| Class (H-M): | 3m - Ditrigonal Pyramidal |
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| Space Group: | R3m |
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| Space Group Setting: | R3m |
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| Cell Parameters: | a = 15.955(3) Å, c = 7.153(2) Å
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| Ratio: | a:c = 1 : 0.448 |
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| Unit Cell Volume: | V 1576.9 ų |
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| Z: | 3 |
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| X-Ray Powder Diffraction: | | d-spacing | | Intensity | | 6.375 | | (19) | | 3.998 | | (22) | | 3.475 | | (100) | | 2.961 | | (60) | | 2.583 | | (67) | | 2.392 | | (14) | | 2.123 | | (14) | | 2.043 | | (19) |
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Optical Data of Fluor-dravite |
| Type: | Uniaxial (-) |
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| RI values: | nω = 1.645() nε = 1.621(2) |
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| Maximum Birefringence: | δ = 0.024
 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: | Visible |
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| Comments: | O = pale yellow-brown, E = colourless |
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Chemical Properties of Fluor-dravite |
| Formula: | |
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| Essential elements: | Al, B, F, H, Mg, Na, O, Si |
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| All elements listed in formula: | Al, B, F, H, Mg, Na, O, Si |
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| Analytical Data: | Average of 10 electron-microprobe analyses; H content by SIMS, Li content by SREF, B2O3 calculated. Sample from the type locality.
SiO2 (36.02)
TiO2 (0.25)
Al2O3 (31.69)
FeO (6.41)
MnO (0.67)
ZnO (0.05)
MgO (7.71)
CaO (0.25)
Na2O (2.80)
Li2O (0.19)
B2O3 (10.91)
H2O (3.19)
F (1.45)
O=F (-0.61)
Total (101.00) |
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| Empirical Formula: | | (Na | | Ca | | )(Mg | | Fe | | Mn | | Zn | | Ti | | Li | | Al | | )Al | | (Si | | Al | | B | | )O | | (BO | | ) | | (OH) | | [F | | (OH) | | ] |
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| Common Impurities: | Ca,Fe,Mn,Li |
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Relationship of Fluor-dravite to other Species |
| Member of: | Tourmaline Group |
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Other Members of Group:
- + | |
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Related Minerals - Nickel-Strunz Grouping):
- + | |
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Other Names for Fluor-dravite |
| Synonyms: | |
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| Other Languages: | |
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Other Information |
| Fluorescence in UV light: | Non-fluorescent |
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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 Fluor-dravite |
Reference List:
- + | Clark, C.M., Hawthorne, F.C., Ottolini, L. (2011): Fluor-dravite, NaMg3Al6Si6O18(BO3)3(OH)3F, a new mineral of the tourmaline group from the Crabtree emerald mine, Mitchell County, North Carolina: description and crystal structure. Canadian Mineralogist, 49, 57-62. |
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Internet Links for Fluor-dravite |
| Search Engines: |
Look for Fluor-dravite on Google
Look for Fluor-dravite images on Google |
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| External Links: | Look for Fluor-dravite on WebmineralLook for Fluor-dravite on Athena MineralogyLook for Fluor-dravite on Mineralien AtlasRaman and XRD data at RRUFF projectAmerican Mineralogist Crystal Structure Database |
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| Jobs: | Mining & Geology Jobs |
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Localities for Fluor-dravite |
The map shows a selection of localities that have latitude and longitude coordinates recorded. Click on the  symbol to view information about a locality.
The  symbol next to localities in the list
can be used to jump to that position on the map.
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