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Dravite

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Formula:
Na(Mg3)Al6(Si6O18)(BO3)3(OH)3(OH)
System:
Trigonal
Colour:
Pale brown to dark-brown ...
Lustre:
Vitreous, Resinous
Hardness:
7
Name:
Named in 1883 by Gustav Tschermak for the river Drau (in Latin, Drave), on which the type locality is situated.

Classification of Dravite

Valid - first described prior to 1959 (pre-IMA) - "Grandfathered"
9.CK.05

9 : SILICATES (Germanates)
C : Cyclosilicates
K : [Si6O18]12- 6-membered single rings, with insular complex anions
Dana 7th ed.:
61.3.1.11
61.3.1.9

61 : CYCLOSILICATES Six-Membered Rings
3 : Six-Membered Rings with borate groups
17.5.27

17 : Silicates Containing other Anions
5 : Borosilicates
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http://www.mindat.org/min-1318.html
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Type Occurrence of Dravite

Year of Discovery:
1883

Occurrences of Dravite

Geological Setting:
Metamorphosed limestones or mafic igneous rocks, rarely in pegmatites or authogenic overgrowths in sedimentary rocks.

Physical Properties of Dravite

Vitreous, Resinous
Diaphaneity (Transparency):
Transparent, Translucent
Colour:
Pale brown to dark-brown to brownish-black, also dark-yellow, blue.
Streak:
Light brown, rarely white.
Hardness (Mohs):
7
Tenacity:
Brittle
Cleavage:
Poor/Indistinct
Very poor {1120} {1011}
Fracture:
Irregular/Uneven, Conchoidal
Density:
3.03 - 3.18 g/cm3 (Measured)    3.038 g/cm3 (Calculated)

Crystallography of Dravite

Crystal System:
Trigonal
Class (H-M):
3m - Ditrigonal Pyramidal
Space Group:
R3m
Cell Parameters:
a = 15.96(2) Å, c = 7.21(2) Å
Ratio:
a:c = 1 : 0.452
Unit Cell Volume:
V 1,590.49 ų (Calculated from Unit Cell)
Z:
3
Morphology:
Equant to short to long prismatic
Twinning:
Rare on {1011} {4041}
X-Ray Powder Diffraction:
Image Loading

Radiation - Copper Kα
Data Set:
Data courtesy of RRUFF project at University of Arizona, used with permission.

Optical Data of Dravite

Type:
Uniaxial (-)
RI values:
nω = 1.634 - 1.661 nε = 1.612 - 1.632
Max Birefringence:
δ = 0.022 - 0.029
Image shows birefringence interference colour range (at 30µm thickness) and does not take into account mineral colouration.
Surface Relief:
Moderate
Pleochroism:
Strong
Comments:
O= pale yellow
E= colorless, yellowish, greenish, brownish

Chemical Properties of Dravite

Formula:
Na(Mg3)Al6(Si6O18)(BO3)3(OH)3(OH)
Essential elements:
All elements listed in formula:
Common Impurities:
Fe,Mn,Ti,Ca,Cr,V,K,F

Relationship of Dravite to other Species

Series:
Forms a series with Schorl (see here)
Forms a series with Elbaite (see here)
Forms a series with Uvite (see here)
Forms a series with Fluor-buergerite (see here)
Other Members of Group:
AdachiiteCaFe3Al6(Si5AlO18)(BO3)3(OH)3(OH)
BosiiteNaFe33+(Al4Mg2)(Si6O18)(BO3)3(OH)3O
Chromium-draviteNa(Mg3)Cr63+(Si6O18)(BO3)3(OH)3(OH)
Chromo-alumino-povondraiteNa(Cr3)(Al4Mg2)(Si6O18)(BO3)3(OH)3O
DarrellhenryiteNa(LiAl2)Al6(BO3)3Si6O18(OH)3O
ElbaiteNa(Li1.5Al1.5)Al6(Si6O18)(BO3)3(OH)3(OH)
FeruviteCa(Fe2+)3MgAl5(Si6O18)(BO3)3(OH)3(OH)
Fluor-buergeriteNa(Fe33+)Al6(Si6O18)(BO3)3O3F
Fluor-draviteNa(Mg3)Al6(Si6O18)(BO3)3(OH)3F
Fluor-elbaiteNa(Li1.5Al1.5)Al6(Si6O18)(BO3)3(OH)3F
Fluor-feruviteCa(Fe2+)3MgAl5(Si6O18)(BO3)3(OH)3F
Fluor-liddicoatiteCa(Li2Al)Al6(Si6O18)(BO3)3(OH)3F
Fluor-schorlNa(Fe32+)Al6(Si6O18)(BO3)3(OH)3F
Fluor-tsilaisiteNa(Mn2+)3Al6(Si6O18)(BO3)3(OH)3F
Fluor-uviteCa(Mg3)MgAl5(Si6O18)(BO3)3(OH)3F
Foitite(□,Na)(Fe22+Al)Al6(Si6O18)(BO3)3(OH)3OH
LiddicoatiteCa(Li2Al)Al6(Si6O18)(BO3)3(OH)3(OH)
Luinaite-(OH)Na(Fe2+)3Al6(Si6O18)(BO3)3(OH)3(OH)
Magnesio-foitite(□,Na)(Mg2Al)Al6(Si6O18)(BO3)3(OH)3(OH)
MaruyamaiteK(MgAl2)(Al5Mg)(BO3)3(Si6O18)(OH)3O
OleniteNa(Al3)Al6(Si6O18)(BO3)3O3(OH)
Oxy-chromium-draviteNa(Cr)3(Cr4Mg2)(Si6O18)(BO3)3(OH)3O
Oxy-draviteNa(MgAl2)MgAl5(Si6O18)(BO3)3(OH)3O
Oxy-rossmanite☐(LiAl2)Al6(Si6O18)(BO3)3(OH)3O
Oxy-schorlNa(Fe22+Al)Al6(Si6O18)(BO3)3(OH)3O
Oxy-vanadium-draviteNa(V)3(V4Mg2)Si6O18(BO3)3(OH)3O
PovondraiteNaFe33+(Mg2Fe43+)(Si6O18)(BO3)3(OH)3O
Rossmanite☐(LiAl2)Al6(Si6O18)(BO3)3(OH)3(OH)
SchorlNa(Fe32+)Al6(Si6O18)(BO3)3(OH)3(OH)
TsilaisiteNa(Mn2+)3Al6(Si6O18)(BO3)3(OH)3(OH)
UM2000-64-SiO:BFeHKMgK, Mg, Fe, Si, B, O, H
Unnamed (Pb-dominant Tourmaline)(Pb,Na)(Li,Al)3Al6(Si6O18)(BO3)3(OH)3(F,OH)
UviteCa(Mg3)MgAl5(Si6O18)(BO3)3(OH)3(F/OH)
Vanadio-oxy-chromium-draviteNa(V)3(Cr4Mg2)(Si6O18)(BO3)3(OH)3O
Vanadio-oxy-draviteNaV3(Al4Mg2)(Si6O18)(BO3)3(OH)3O
9.CK.Fluor-schorlNa(Fe32+)Al6(Si6O18)(BO3)3(OH)3F
9.CK.05Fluor-buergeriteNa(Fe33+)Al6(Si6O18)(BO3)3O3F
9.CK.05Chromium-draviteNa(Mg3)Cr63+(Si6O18)(BO3)3(OH)3(OH)
9.CK.05ElbaiteNa(Li1.5Al1.5)Al6(Si6O18)(BO3)3(OH)3(OH)
9.CK.05FeruviteCa(Fe2+)3MgAl5(Si6O18)(BO3)3(OH)3(OH)
9.CK.05Foitite(□,Na)(Fe22+Al)Al6(Si6O18)(BO3)3(OH)3OH
9.CK.05LiddicoatiteCa(Li2Al)Al6(Si6O18)(BO3)3(OH)3(OH)
9.CK.05OleniteNa(Al3)Al6(Si6O18)(BO3)3O3(OH)
9.CK.05PovondraiteNaFe33+(Mg2Fe43+)(Si6O18)(BO3)3(OH)3O
9.CK.05SchorlNa(Fe32+)Al6(Si6O18)(BO3)3(OH)3(OH)
9.CK.05Magnesio-foitite(□,Na)(Mg2Al)Al6(Si6O18)(BO3)3(OH)3(OH)
9.CK.05Rossmanite☐(LiAl2)Al6(Si6O18)(BO3)3(OH)3(OH)
9.CK.05Oxy-vanadium-draviteNa(V)3(V4Mg2)Si6O18(BO3)3(OH)3O
9.CK.05Oxy-draviteNa(MgAl2)MgAl5(Si6O18)(BO3)3(OH)3O
9.CK.05Oxy-rossmanite☐(LiAl2)Al6(Si6O18)(BO3)3(OH)3O
9.CK.05Chromo-alumino-povondraiteNa(Cr3)(Al4Mg2)(Si6O18)(BO3)3(OH)3O
9.CK.05Fluor-draviteNa(Mg3)Al6(Si6O18)(BO3)3(OH)3F
9.CK.05Fluor-uviteCa(Mg3)MgAl5(Si6O18)(BO3)3(OH)3F
9.CK.10Abenakiite-(Ce)Na26Ce6(Si6O18)(PO4)6(CO3)6(SO3)
9.CK.15ScawtiteCa7(Si3O9)2CO3 · 2H2O
9.CK.20Steenstrupine-(Ce)Na14Mn22+(Fe3+,Mn3+)2Ce6(Zr,Th)(Si6O18)2(PO4)6(HPO4)(OH)2 · 2H2O
9.CK.20ThorosteenstrupineCaMnThSi4O11(OH)F · 6H2O
17.5.1ManandoniteLi2Al4(Si2AlB)O10(OH)8
17.5.2ReedmergneriteNa[BSi3O8]
17.5.3SearlesiteNa(H2BSi2O7)
17.5.4OleniteNa(Al3)Al6(Si6O18)(BO3)3O3(OH)
17.5.5ElbaiteNa(Li1.5Al1.5)Al6(Si6O18)(BO3)3(OH)3(OH)
17.5.6KalborsiteK6Al4BSi6O20(OH)4Cl
17.5.7BoromuscoviteKAl2(BSi3O10)(OH)2
17.5.8PoudretteiteKNa2B3Si12O30
17.5.9LiddicoatiteCa(Li2Al)Al6(Si6O18)(BO3)3(OH)3(OH)
17.5.10DatoliteCa(HBSiO5)
17.5.11DanburiteCaB2Si2O8
17.5.12HowliteCa2B5SiO9(OH)5
17.5.13BakeriteCa4(H5B5Si3O20)
17.5.14OyeliteCa10Si8B2O29 · 12.5H2O
17.5.15KornerupineMg3Al6(Si,Al,B)5O21(OH)
17.5.16HarkeriteCa12Mg4Al(BO3)3(SiO4)4(CO3)5 · H2O
17.5.17Serendibite(Ca,Na)2(Mg,Fe2+)3(Al,Fe3+)3[O2|(Si,Al,B)6O18]
17.5.18Stillwellite-(Ce)(Ce,La,Ca)BSiO5
17.5.19Tadzhikite-(Ce)(Ca,Ce)4(Ce,Y)2(Ti4+,Fe3+,Al)[B4Si4O22](OH)2
17.5.20Melanocerite-(Ce)(Ce,Ca)5(SiO4,BO4)3(OH,0)
17.5.21Okanoganite-(Y)(Na,Ca)3(Y,Ce)12Si6B2O27F14
17.5.22Tritomite-(Ce)(Ce,La,Y,Th)5(Si,B)3(O,OH,F)13
17.5.23Tritomite-(Y)(Y,Ca,La,Fe)5(Si,B,Al)3(O,OH,F)13
17.5.24Cappelenite-(Y)Ba(Y,Ce)6Si3B6O24F2
17.5.25Dumortierite(Al,Fe3+)7(SiO4)3(BO3)O3
17.5.26Holtite(Ta0.60.4)Al6BSi3O18(O,OH)2.25
17.5.28 Ferridravite
17.5.29Axinite-(Mg)Ca2MgAl2BSi4O15OH
17.5.30UviteCa(Mg3)MgAl5(Si6O18)(BO3)3(OH)3(F/OH)
17.5.31GarrelsiteBa3NaSi2B7O16(OH)4
17.5.32TienshaniteKNa3Na6Ca2Ba6Mn6(Ti4+,Nb)6B12Si36O114(O,OH,F)11
17.5.33LeucospheniteBaNa4Ti2B2Si10O30
17.5.34TaramelliteBa4(Fe3+,Ti,Fe2+,Mg)4(B2Si8O27)O2Clx
17.5.35TitantaramelliteBa4(Ti,Fe3+,Fe2+,Mg)4(B2Si8O27)O2Clx
17.5.36NagashimaliteBa4(V,Ti)4B2Si8O27(O,OH)2Cl
17.5.37Chromium-draviteNa(Mg3)Cr63+(Si6O18)(BO3)3(OH)3(OH)
17.5.38WawayandaiteCa6Mn2BBe9Si6O23(OH,Cl)15
17.5.39Werdingite(Mg,Fe)2Al14Si4B4O37
17.5.40Axinite-(Mn)Ca2Mn2+Al2BSi4O15(OH)
17.5.41Axinite
17.5.42Tinzenite(Ca,Mn2+)2Mn2+Al2BSi4O15(OH)
17.5.44SchorlNa(Fe32+)Al6(Si6O18)(BO3)3(OH)3(OH)
17.5.45Fluor-buergeriteNa(Fe33+)Al6(Si6O18)(BO3)3O3F
17.5.46FeruviteCa(Fe2+)3MgAl5(Si6O18)(BO3)3(OH)3(OH)
17.5.47Axinite-(Fe)Ca2Fe2+Al2BSi4O15OH
17.5.48HomiliteCa2(Fe2+,Mg)B2Si2O10
17.5.49Grandidierite(Mg,Fe2+)(Al,Fe3+)3(SiO4)(BO3)O2
17.5.50Hyalotekite(Pb,Ba,K)4(Ca,Y)2(B,Be)2(Si,B)2Si8O28(F,Cl)
17.5.51Hellandite-(Y)(Ca,REE)4Y2Al(Be,Li)2-xB4Si4O22(OH)2
61.3.1.1Foitite(□,Na)(Fe22+Al)Al6(Si6O18)(BO3)3(OH)3OH
61.3.1.2Magnesio-foitite(□,Na)(Mg2Al)Al6(Si6O18)(BO3)3(OH)3(OH)
61.3.1.3Rossmanite☐(LiAl2)Al6(Si6O18)(BO3)3(OH)3(OH)
61.3.1.4LiddicoatiteCa(Li2Al)Al6(Si6O18)(BO3)3(OH)3(OH)
61.3.1.5UviteCa(Mg3)MgAl5(Si6O18)(BO3)3(OH)3(F/OH)
61.3.1.5Fluor-uviteCa(Mg3)MgAl5(Si6O18)(BO3)3(OH)3F
61.3.1.6FeruviteCa(Fe2+)3MgAl5(Si6O18)(BO3)3(OH)3(OH)
61.3.1.7Fluor-buergeriteNa(Fe33+)Al6(Si6O18)(BO3)3O3F
61.3.1.8PovondraiteNaFe33+(Mg2Fe43+)(Si6O18)(BO3)3(OH)3O
61.3.1.9OleniteNa(Al3)Al6(Si6O18)(BO3)3O3(OH)
61.3.1.10ElbaiteNa(Li1.5Al1.5)Al6(Si6O18)(BO3)3(OH)3(OH)
61.3.1.12SchorlNa(Fe32+)Al6(Si6O18)(BO3)3(OH)3(OH)
61.3.1.13Chromium-draviteNa(Mg3)Cr63+(Si6O18)(BO3)3(OH)3(OH)
61.3.1.14Oxy-vanadium-draviteNa(V)3(V4Mg2)Si6O18(BO3)3(OH)3O

Other Names for Dravite

Name in Other Languages:

Other Information

Electrical:
Pyroelectric, piezoelectric
Health Risks:
No information on health risks for this material has been entered into the database. You should always treat mineral specimens with care.

References for Dravite

Reference List:
Barsanov, G.P. and Yakovleva, M.E. (1964) Tourmalines of dravite composition. Akademiya Nauk SSSR, Mineralogicheshkii Muzei, Moscow: 15: 39-80.

Manning, P.G. (1969) An optical absorption study of the origin of colour and pleochroism in pink and brown tourmalines. Canadian Mineralogist: 9: 678-690.

Dunn, P.J. (1977): Chromium in dravite. Mineral. Mag., 41, 408-410.

Povondra, P. (1981) The crystal chemistry of tourmalines of the schorl-dravite series. Acta Univ. Carol., Geol. 3: 223-264.

Foit, F.F., Jr. (1992) X-ray and optical data for a vanadium-rich dravite from Silver Knob, Mariposa County, California, U.S.A. Powder Diffraction: 7: 236-238.

Hawthorne, F.C., D.J. MacDonald, and .C. Burns (1993), Reassignment of cation site-occupancies in tourmaline: Al-Mg disorder in the crystal structure of dravite: American Mineralogist: 78: 265-270.

Grew, E.S. and Anovitz, L.M. (1996) BORON: Mineralogy, Petrology and Geochemistry, second edition, as revised (2002).

Novák, M. (1998) Blue dravite as an indicator of fluid composition during subsolidus replacement processes in Li-poor granitic pegmatites in the Modanubicum, Czech Republic. Journal of the Czech Geological Society: 43: 24-30.

Bloodaxe, E.S., J.M. Hughes, M.D. Dyar, E.S. Grew, and C.V. Guidotti (1999): Linking structure and chemistry in the schorl-dravite series: American Mineralogist: 84: 922-928.

Ertl, A., Pertlik, F., and Bernhardt, H.-J. (2001) Ein hell-blauer Olenit-Schörl-Dravit Mischkristall von Ebersdorf, Niederösterreich: Strukturanalyse und Chemie. Mitt. Österr. Mineral. Ges.: 146: 75-77. (in German)

Bosi, F. & Lucchesi, S. (2004): Crystal chemistry of the schorl-dravite series. European Journal of Mineralogy 16, 335-344.

Ertl, A. (2007): Über die Typlokalität und die Nomenklatur des Minerals Dravit. Mitteilungen der Österreichischen Mineralogischen Gesellschaft, 153, 265-271. [http://www.uibk.ac.at/mineralogie/oemg/bd_153/153_265-271x.pdf]

Ertl, A., Mali, H., Schuster, R., Körner, W., Hughes, J.M., Brandstätter, F. & Tillmanns, E. (2010): Li-bearing, disordered Mg-rich tourmalines from the pegmatite-marble contact from the Austroalpine basement units (Styria, Austria). Mineral. Petrol., 99, 89-104. [Li-bearing dravite]

Hughes, J.M., Rakovan, J., Ertl, A., Rossman, G.R., Baksheev, I. & Bernhardt, H.-J. (2011): Dissymetrization in tourmaline: The atomic arrangement of sectorally zoned triclinic Ni-bearing dravite. Canadian Mineralogist 49, 29-40.

Internet Links for Dravite

Localities for Dravite

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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