Dravite Mineral Data
General Dravite Information
Chemical Formula: NaMg3Al6(BO3)3Si6O18(OH)4
Composition: Molecular Weight = 958.75 gm
Sodium 2.40 % Na 3.23 % Na2 O
Magnesium 7.61 % Mg 12.61 % MgO
Aluminum 16.89 % Al 31.90 % Al2 O3
Silicon 17.58 % Si 37.60 % SiO2
Boron 3.38 % B 10.89 % B2 O3
Hydrogen 0.42 % H 3.76 % H2 O
Oxygen 51.73 % O
______ ______
100.00 % 100.00 % = TOTAL OXIDE
Empirical Formula: NaMg3 Al6 (BO3 )3 Si6 O18 (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)
ICSD 72937
PDF 44-1457
Tourmaline
Dravite Image
Images:
Dravite
Comments: Doubly terminated dravite crystal on white mica shist matrix.Location: Yinnietharra Station, Gascoyne, Western Australia.
Scale: 4 x 4 x 2.9 cm.© Fabre Minerals
Images:
Dravite
Comments: Greenish-brown chrome-rich dravite tourmaline crystals up to 13 mm long with complex terminations. Fluoresces mildly under UV illumination.Location: Shako Ranch, Mwatate Kabanga, Voi, Taita-Taveta district, Coast Province, Kenya.
Scale: 14x13x10 mm.© John Betts - Fine Minerals
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 Pyramidal
X Ray Diffraction: By Intensity(I/Io ): 2.576(1), 2.961(0.85), 3.99(0.85),
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 ) calc = 0.009 (Superior) - where the CI = (1-KPDcalc /KC )PDcalc = 0.21,KPDmeas = 0.2045,KC = 0.2118
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
Fermion Index: Fermion Index = 0.02
Photoelectric: PEDravite = 1.42 barns/electronU=PEDravite x r Electron Density= 4.25 barns/cc.
Radioactivity: GRapi = 0 (Gamma Ray American Petroleum Institute Units)Not Radioactive
Dravite Classification
Dana Class: 61.03e.01.09 (61) Cyclosilicate Six-Membered Rings
(61.03e) with borate groups (Sodic Tourmaline Subgroup)
(61.03e.01) Schorl Subgroup
61.03e.01.09 Dravite ! NaMg3Al6(BO3)3Si6O18(OH)4 R 3m 3m
61.03e.01.10 Schorl ! NaFe3Al6(BO3)3Si6O18(OH)4 R 3m 3m
61.03e.01.10a Schorl-(F) ! NaFe3Al6Si6O18)(BO3)3(OH)3(F,OH) R 3m 3m
61.03e.01.11 Chromdravite ! NaMg3(Cr,Fe)6(BO3)3Si6O18(OH)4 R 3m 3m
61.03e.01.12 Vanadiumdravite ! NaMg3V6(Si6O18)(BO3)3(OH)4 R 3m 3m
Strunz Class: 09.CK.05 09 - SILICATES (Germanates)
09.C - Cyclosilicates
09.CK -[Si6O18]12- 6-membered single rings, with insular complex anions
09.CK.05 Chromdravite ! NaMg3(Cr,Fe)6(BO3)3Si6O18(OH)4 R 3m 3m
09.CK.05 Feruvite ! (Ca,Na)(Fe,Mg,Ti)3(Al,Mg,Fe)6(BO3)3Si6O18(OH)4 R 3m 3m
09.CK.05 Dravite NaMg3Al6(BO3)3Si6O18(OH)4 R 3m 3m
09.CK.05 Buergerite ! NaFe3Al6(BO3)3Si6O21F R 3m 3m
09.CK.05 Foitite ! []Na<0.5(Fe,Al)3Al6Si6O18(BO3)3(OH)4 R 3m 3m
09.CK.05 Liddicoatite ! Ca(Li,Al)3Al6(BO3)3Si6O18(O,OH,F)4 R 3m 3m
09.CK.05 Elbaite Na(Li,Al)3Al6(BO3)3Si6O18(OH)4 R 3m 3m
09.CK.05 Rossmanite ! []LiAl2Al6(Si6O18)(BO3)3(OH)4 R 3m 3m
09.CK.05 Olenite ! NaAl3Al6(BO3)3(Si6O18)(O,OH)4 R 3m 3m
09.CK.05 Povondraite ! (Na,K)(Fe,Fe)3(Fe,Mg,Al)6(BO3)3Si6O18(OH)4 R 3m 3m
09.CK.05 Schorl NaFe3Al6(BO3)3Si6O18(OH)4 R 3m 3m
09.CK.05 Uvite (Ca,Na)(Mg,Fe)3Al5Mg(BO3)3Si6O18(OH,F)4 R 3m 3m
09.CK.05 Vanadiumdravite ! NaMg3V6(Si6O18)(BO3)3(OH)4 R 3m 3m
09.CK.05 Magnesiofoitite ! [](Mg2Al)Al6(Si6O18)(BO3)3(OH)4 R 3m 3m
09.CK.05 Hydroxyuvite ! CaMg3(Al5Mg)(Si6O18)(BO3)3(OH)3(OH) R 3m 3m
09.CK.05 Schorl-(F) ! NaFe3Al6Si6O18)(BO3)3(OH)3(F,OH) R 3m 3m
Other Dravite Information
References: NAME( Duda&Rejl90) PHYS. PROP.(Dana8) OPTIC PROP.(Heinrich65)
See Also: Links to other databases for Dravite : Alkali-Nuts(English) Alkali-Nuts(Francais) Am. Min. Crystal Structure Database Amethyst Galleries' Mineral Gallery Athena CalTech Mineral Spectroscopy EUROmin Project Ecole des Mines de Paris Franklin Minerals(Dunn) GeoScienceWorld Google Images Google Scholar Handbook of Mineralogy (MinSocAm) Handbook of Mineralogy (UofA) HyperPhysics MinDAT Mineral and Gemstone Kingdom Mineralienatlas (Deutsch) Online Mineral Museum QUT Mineral Atlas Ruff.Info Scandinavian mineral gallery Tradeshop.com - The Rainbow of Gems WWW-MINCRYST Search for Dravite using:
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Dravite
NaMg3Al6(BO3)3Si6O18(OH)4 Dana No: 61.03e.01.09 Strunz No: 09.CK.05 Locality:
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Chemical Formula: 
