General Dravite Information Chemical Formula: |
NaMg3Al6(BO3)3Si6O18(OH)4 |
Composition: |
Molecular Weight = 958.75 gm |
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Sodium 2.40 % Na 3.23 % Na2O |
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Magnesium 7.61 % Mg 12.61 % MgO |
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Aluminum 16.89 % Al 31.90 % Al2O3 |
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Silicon 17.58 % Si 37.60 % SiO2 |
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Boron 3.38 % B 10.89 % B2O3 |
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Hydrogen 0.42 % H 3.76 % H2O |
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Oxygen 51.73 % O |
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______ ______ |
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100.00 % 100.00 % = TOTAL OXIDE |
Empirical Formula: |
NaMg3Al6(BO3)3Si6O18(OH)4 |
Environment: |
Metasomatically altered magnesian or dolomitic limestones in contact-metamorphic aureoles. |
IMA Status: |
Valid Species (Pre-IMA) 1883 (Dana # Changed) |
Locality: |
Drava River, Austria. Link to MinDat.org Location Data. |
Name Origin: |
Named for the locality. |
Name Pronunciation: |
Dravite |
Synonym: |
Dravite - (61.3.1.9) |
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ICSD 72937 |
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PDF 44-1457 |
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Tourmaline |
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Dravite Crystallography Axial Ratios: |
a:c = 1:0.45172 |
Cell Dimensions: |
a = 15.941, c = 7.201, Z = 3; V = 1,584.73 Den(Calc)= 3.01 |
Crystal System: |
Trigonal - Ditrigonal PyramidalH-M Symbol (3m) Space Group: R 3m |
X Ray Diffraction: |
By Intensity(I/Io): 2.576(1), 2.961(0.85), 3.99(0.85), |
Crystal Structure:
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Mouse
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| Physical Properties of Dravite Cleavage: |
{???} Indistinct |
Color: |
Black, Green, Red, Blue, White. |
Density: |
2.98 - 3.2, Average = 3.09 |
Diaphaneity: |
Transparent to translucent to opaque |
Fracture: |
Sub Conchoidal - Fractures developed in brittle materials characterized by semi-curving surfaces. |
Habit: |
Columnar - Forms columns |
Habit: |
Divergent - Crystals radiate from a center without producing stellar forms. |
Habit: |
Massive - Uniformly indistinguishable crystals forming large masses. |
Hardness: |
7-7.5 - Quartz-Garnet |
Luminescence: |
Fluorescent, Short UV=yellow to orange. |
Luster: |
Vitreous - Resinous |
Streak: |
colorless |
| Optical Properties of Dravite Dichroism (e): |
pale yellow or colorless. |
Dichroism (w): |
dark yellowish brown or light yellow. |
Gladstone-Dale: |
CI meas= 0.034 (Excellent) - where the CI = (1-KPDmeas/KC) |
CI calc= 0.009 (Superior) - where the CI = (1-KPDcalc/KC) KPDcalc= 0.21,KPDmeas= 0.2045,KC= 0.2118 Ncalc = 1.63 - 1.68 Optical Data: |
Uniaxial (-), e=1.612-1.63, w=1.631-1.655, bire=0.0190-0.0250. |
| Calculated Properties of Dravite Electron Density: |
Bulk Density (Electron Density)=2.99 gm/cc |
note: Specific Gravity of Dravite =3.01 gm/cc. Fermion Index: |
Fermion Index = 0.02 |
Boson Index = 0.98 Photoelectric: |
PEDravite = 1.42 barns/electron |
U=PEDravite x rElectron Density= 4.25 barns/cc. Radioactivity: |
GRapi = 0 (Gamma Ray American Petroleum Institute Units) |
Dravite is Not Radioactive | Dravite Classification Dana Class: |
61.03e.01.09 (61)Cyclosilicate Six-Membered Rings |
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(61.03e)with borate groups (Sodic Tourmaline Subgroup) |
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(61.03e.01)Schorl Subgroup |
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Strunz Class: |
09.CK.05 09 - SILICATES (Germanates) |
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09.C - Cyclosilicates |
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09.CK -[Si6O18]12- 6-membered single rings, with insular complex anions |
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| Other Dravite Information References: |
NAME( Duda&Rejl90) PHYS. PROP.(Dana8) OPTIC PROP.(Heinrich65) |
See Also: |
Links to other databases for Dravite : |
1 - Alkali-Nuts(English) 2 - Alkali-Nuts(Francais) 3 - Am. Min. Crystal Structure Database 4 - Amethyst Galleries' Mineral Gallery 5 - Athena 6 - CalTech Mineral Spectroscopy 7 - EUROmin Project 8 - Ecole des Mines de Paris 9 - Franklin Minerals(Dunn) 10 - GeoScienceWorld 11 - Google Images 12 - Google Scholar 13 - Handbook of Mineralogy (MinSocAm) 14 - Handbook of Mineralogy (UofA) 15 - HyperPhysics 16 - MinDAT 17 - Mineral and Gemstone Kingdom 18 - Mineralienatlas (Deutsch) 19 - Online Mineral Museum 20 - QUT Mineral Atlas 21 - Ruff.Info 22 - Scandinavian mineral gallery 23 - Tradeshop.com - The Rainbow of Gems 24 - WWW-MINCRYST Search for Dravite using: Visit our Advertisers for Dravite : A Bijoux Google Search for DraviteAdam's Minerals Google Search for Dravite Cape Minerals Google Search for Dravite Dakota Matrix Minerals Google Search for Dravite Excalibur Mineral Corp. Google Search for Dravite Exceptional Minerals Google Search for Dravite John Betts Fine Minerals Search for Dravite McDougall Minerals Google Search for Dravite Mineral News Website Link Rock and Mineral Shows Google Search for Dravite Weinrich Minerals, Inc. Google Search for Dravite Ask about Dravite here : Print or Cut-and-Paste your Dravite Specimen Label here :
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