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Dravite

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Reese Farm (Dale Bush Farm; Jones Farm), Gouverneur, St Lawrence Co., New York, USA
© 2002 John H. Betts

Show Dravite Photos (163)
Formula:
[Na][Mg
 
3
][Al
 
6
][(OH)
 
3
|OH|(BO
 
3
)
 
3
|Si
 
6
O
 
18
]
System:TrigonalColour:Pale brown to dark-brown ...
Lustre:Vitreous, ResinousHardness:7
Name:Named for the river Drau (in Latin, Drave), on which the type locality is situated.


Tourmaline Group. Dravite-Elbaite Series. Schorl-Dravite Series.

Classification of Dravite

IMA status:Valid - first described prior to 1959 (pre-IMA) - "Grandfathered"
Strunz 8th edition ID:8/E.19-20
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
Dana 7th edition ID:61.3.1.11
Dana 8th edition ID:61.3.1.9

61 : CYCLOSILICATES Six-Membered Rings
3 : Six-Membered Rings with borate groups
Hey's CIM Ref.:17.5.27

17 : Silicates Containing other Anions
5 : Borosilicates
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Type Occurrence of Dravite

Type Locality:Dobrova, Dravograd (Unterdrauburg), Slovenia
Year of Discovery:1883

Occurrences of Dravite

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

Physical Properties of Dravite

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

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:
Horizontal Axis: ° to ° Vertical Axis: % Source Data: Filtered Data: Peaks:
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
Maximum Birefringence:δ = 0.022 - 0.029

Chart 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][Mg
 
3
][Al
 
6
][(OH)
 
3
|OH|(BO
 
3
)
 
3
|Si
 
6
O
 
18
]
Essential elements:Al, B, H, Mg, Na, O, Si
All elements listed in formula:Al, B, H, Mg, Na, O, Si
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 Buergerite (see here)
Member of:Tourmaline
Related Minerals - Nickel-Strunz Grouping):

- +
9.CK.05Buergerite
[Na][Fe
3+
3
][Al
 
6
][O
 
3
|F|(BO
 
3
)
 
3
|Si
 
6
O
 
18
]
9.CK.05Chromdravite
[Na][Mg
 
3
][(Cr
3+
 
,Fe
3+
 
)
 
6
][(OH)
 
3
|OH|(BO
 
3
)
 
3
|Si
 
6
O
 
18
]
9.CK.05Elbaite
[Na][(Li,Al)
 
3
][Al
 
6
][(OH)
 
3
|OH|(BO
 
3
)
 
3
|Si
 
6
O
 
18
]
9.CK.05Feruvite
[Ca][(Fe
2+
 
 ,Mg)
 
3
][MgAl
 
5
][(OH)
 
3
|OH|(BO
 
3
)
 
3
|Si
 
6
O
 
18
]
9.CK.05Foitite
[ ][Fe
2+
2
(Al,Fe
3+
 
)][Al
 
6
][(OH)
 
3
|OH|(BO
 
3
)
 
3
|Si
 
6
O
 
18
]
9.CK.05Liddicoatite
[Ca][Li
 
2
Al][Al
 
6
][(OH)
 
3
|F|(BO
 
3
)
 
3
|Si
 
6
O
 
18
]
9.CK.05Olenite
(Na,[ ])[(Al,Li)
 
3
][Al
 
6
][(O,OH)
 
3
|OH|(BO
 
3
)
 
3
|Si
 
6
O
 
18
]
9.CK.05Povondraite
[Na][Fe
3+
3
][Fe
3+
4
Mg
 
2
][(OH)
 
3
|F|(BO
 
3
)
 
3
|Si
 
6
O
 
18
]
9.CK.05Schorl
[Na][Fe
2+
3
][Al
 
6
][(OH)
 
3
|OH|(BO
 
3
)
 
3
|Si
 
6
O
 
18
]
9.CK.05Uvite
[Ca][(Mg,Fe
2+
 
)
 
3
][MgAl
 
5
][(OH)
 
3
|OH|(BO
 
3
)
 
3
|Si
 
6
O
 
18
]
9.CK.05Magnesiofoitite
[ ][Mg
 
2
(Al,Fe
3+
 
 )][Al
 
6
][(OH)
 
3
|OH|(BO
 
3
)
 
3
|Si
 
6
O
 
18
]
9.CK.05Rossmanite
[ ][LiAl
 
2
][Al
 
6
][(OH)
 
3
|OH|(BO
 
3
)
 
3
|Si
 
6
O
 
18
]
9.CK.05Vanadiumdravite
[Na][Mg
 
3
][V
3+
6
][(OH)
 
3
|OH|(BO
 
3
)
 
3
|Si
 
6
O
 
18
]
9.CK.05Oxy-Dravite
Na (MgAl
 
2
)(MgAl
 
5
)Si
 
6
O
 
18
(BO
 
3
)
 
3
(OH)
 
3
O
9.CK.05Oxy-rossmanite
[ ][LiAl
 
2
]Al
 
6
(BO
 
3
)
 
3
[Si
 
6
O
 
18
](OH)
 
3
(O)
9.CK.10Abenakiite-(Ce)
Na
 
26
Ce
 
6
[O|SO
 
2
|(CO
 
3
)
 
6
|(PO
 
4
)
 
6
|Si
 
6
O
 
18
]
9.CK.15Scawtite
Ca
 
7
Si
 
6
(CO
 
3
)O
 
18
·2H
 
2
O
9.CK.20Steenstrupine-(Ce)
Na
 
14
Mn
2+
2
(Fe
3+
 
,Mn
3+
 
)
 
2
Ce
 
6
(Zr,Th)[(OH)
 
2
|HPO
 
4
|(PO
 
4
)
 
6
|(Si
 
6
O
 
18
)
 
2
]·2H
 
2
O
9.CK.20Thorosteenstrupine
CaMnThSi
 
4
O
 
11
(OH)F·6H
 
2
O
Related Minerals - Hey's Index Grouping:

- +
17.5.1Manandonite
LiAl
 
4
Si
 
3
BO
 
10
(OH)
 
6
17.5.2Reedmergnerite
Na[BSi
 
3
O
 
8
]
17.5.3Searlesite
NaBSi
 
2
O
 
5
(OH)
 
2
17.5.4Olenite
(Na,[ ])[(Al,Li)
 
3
][Al
 
6
][(O,OH)
 
3
|OH|(BO
 
3
)
 
3
|Si
 
6
O
 
18
]
17.5.5Elbaite
[Na][(Li,Al)
 
3
][Al
 
6
][(OH)
 
3
|OH|(BO
 
3
)
 
3
|Si
 
6
O
 
18
]
17.5.6Kalborsite
K
 
6
[Cl|B(OH)
 
4
|Al
 
4
Si
 
6
O
 
20
]
17.5.7Boromuscovite
KAl
 
2
[(OH)
 
2
|BSi
 
3
O
 
10
]
17.5.8Poudretteite
KNa
 
2
B
 
3
Si
 
12
O
 
30
17.5.9Liddicoatite
[Ca][Li
 
2
Al][Al
 
6
][(OH)
 
3
|F|(BO
 
3
)
 
3
|Si
 
6
O
 
18
]
17.5.10Datolite
CaB[OH|SiO
 
4
]
17.5.11Danburite
CaB
 
2
Si
 
2
O
 
8
17.5.12Howlite
Ca
 
2
B
 
5
SiO
 
9
(OH)
 
5
17.5.13Bakerite
Ca
 
4
B
 
4
[(OH)
 
4
|HBO
 
4
|(SiO
 
4
)
 
3
]
17.5.14Oyelite
Ca
 
10
Si
 
8
B
 
2
O
 
29
·12.5H
 
2
O
17.5.15Kornerupine
Mg
 
3
Al
 
6
(Si,Al,B)
 
5
O
 
21
(OH)
17.5.16Harkerite
Ca
 
24
Mg
 
8
Al
 
2
Si
 
8
(O,OH)
 
32
(BO
 
3
)
 
8
(CO
 
3
)
 
8
(H
 
2
O,Cl)
17.5.17Serendibite
(Ca,Na)
 
2
(Mg,Fe
2+
 
)
 
3
(Al,Fe
3+
 
)
 
3
[O
 
2
|(Si,Al,B)
 
6
O
 
18
]
17.5.18Stillwellite-(Ce)
(Ce,La,Ca)BSiO
 
5
17.5.19Tadzhikite-(Ce)
(Ca,Ce)
 
4
(Ce,Y)
 
2
(Ti
4+
 
,Fe
3+
 
,Al)[B
 
4
Si
 
4
O
 
22
](OH)
 
2
17.5.20Melanocerite-(Ce)
(Ce,Ca)
 
5
(Si,B)
 
3
O
 
12
(OH,F)·nH
 
2
O
17.5.21Okanoganite-(Y)
(Na,Ca)
 
3
(Y,Ce)
 
12
Si
 
6
B
 
2
O
 
27
F
 
14
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)
 
6
Si
 
3
B
 
6
O
 
24
F
 
2
17.5.25Dumortierite
(Al,Fe
3+
 
)
 
7
[O
 
3
|BO
 
3
|(SiO
 
4
)
 
3
]
17.5.26Holtite
(Ta,Sb)Al
 
6
[O
 
3
|BO
 
3
|(SiO
 
4
)
 
3
]
17.5.28 Ferridravite
17.5.29Axinite-(Mg)
Ca
 
2
MgAl
 
2
[OH|BSi
 
4
O
 
15
]
17.5.30Uvite
[Ca][(Mg,Fe
2+
 
)
 
3
][MgAl
 
5
][(OH)
 
3
|OH|(BO
 
3
)
 
3
|Si
 
6
O
 
18
]
17.5.31Garrelsite
Ba
 
3
NaSi
 
2
B
 
7
O
 
16
(OH)
 
4
17.5.32Tienshanite
KNa
 
3
Na
 
6
Ca
 
2
Ba
 
6
Mn
 
6
(Ti
4+
 
,Nb)
 
6
B
 
12
Si
 
36
O
 
114
(O,OH,F)
 
11
17.5.33Leucosphenite
BaNa
 
4
Ti
 
2
B
 
2
Si
 
10
O
 
30
17.5.34Taramellite
Ba
 
4
(Fe
3+
 
,Ti,Fe
2+
 
,Mg)
 
4
(B
 
2
Si
 
8
O
 
27
)O
 
2
Cl
 
x
17.5.35Titantaramellite
Ba
 
4
(Ti,Fe
3+
 
,Fe
2+
 
,Mg)
 
4
(B
 
2
Si
 
8
O
 
27
)O
 
2
Cl
 
x
17.5.36Nagashimalite
Ba
 
4
(V,Ti)
 
4
B
 
2
Si
 
8
O
 
27
(O,OH)
 
2
Cl
17.5.37Chromdravite
[Na][Mg
 
3
][(Cr
3+
 
,Fe
3+
 
)
 
6
][(OH)
 
3
|OH|(BO
 
3
)
 
3
|Si
 
6
O
 
18
]
17.5.38Wawayandaite
Ca
 
6
Mn
 
2
BBe
 
9
Si
 
6
O
 
23
(OH,Cl)
 
15
17.5.39Werdingite
(Mg,Fe)
 
2
Al
 
14
Si
 
4
B
 
4
O
 
37
17.5.40Axinite-(Mn)
Ca
 
2
Mn
2+
 
Al
 
2
[OH|BSi
 
4
O
 
15
]
17.5.41Axinite
17.5.42Tinzenite
(Ca,Mn
2+
 
,Fe
2+
 
)
 
3
Al
 
2
[OH|BSi
 
4
O
 
15
]
17.5.44Schorl
[Na][Fe
2+
3
][Al
 
6
][(OH)
 
3
|OH|(BO
 
3
)
 
3
|Si
 
6
O
 
18
]
17.5.45Buergerite
[Na][Fe
3+
3
][Al
 
6
][O
 
3
|F|(BO
 
3
)
 
3
|Si
 
6
O
 
18
]
17.5.46Feruvite
[Ca][(Fe
2+
 
 ,Mg)
 
3
][MgAl
 
5
][(OH)
 
3
|OH|(BO
 
3
)
 
3
|Si
 
6
O
 
18
]
17.5.47Axinite-(Fe)
Ca
 
2
Fe
2+
 
Al
 
2
[OH|BSi
 
4
O
 
15
]
17.5.48Homilite
Ca
 
2
(Fe
2+
 
,Mg)B
 
2
[O|SiO
 
4
]
 
2
17.5.49Grandidierite
(Mg,Fe
2+
 
)(Al,Fe
3+
 
)
 
3
[O
 
2
|BO
 
3
|SiO
 
4
]
17.5.50Hyalotekite
(Ba,Pb,Ca,K)
 
6
(B,Si,Al)
 
2
(Si,Be)
 
10
O
 
28
(F,Cl)
17.5.51Hellandite-(Y)
(Ca,Y)
 
6
(Al,Fe
3+
 
)Si
 
4
B
 
4
O
 
20
(OH)
 
4
Related Minerals - Dana Grouping):

- +
61.3.1.1Foitite
[ ][Fe
2+
2
(Al,Fe
3+
 
)][Al
 
6
][(OH)
 
3
|OH|(BO
 
3
)
 
3
|Si
 
6
O
 
18
]
61.3.1.2Magnesiofoitite
[ ][Mg
 
2
(Al,Fe
3+
 
 )][Al
 
6
][(OH)
 
3
|OH|(BO
 
3
)
 
3
|Si
 
6
O
 
18
]
61.3.1.3Rossmanite
[ ][LiAl
 
2
][Al
 
6
][(OH)
 
3
|OH|(BO
 
3
)
 
3
|Si
 
6
O
 
18
]
61.3.1.4Liddicoatite
[Ca][Li
 
2
Al][Al
 
6
][(OH)
 
3
|F|(BO
 
3
)
 
3
|Si
 
6
O
 
18
]
61.3.1.5Uvite
[Ca][(Mg,Fe
2+
 
)
 
3
][MgAl
 
5
][(OH)
 
3
|OH|(BO
 
3
)
 
3
|Si
 
6
O
 
18
]
61.3.1.6Feruvite
[Ca][(Fe
2+
 
 ,Mg)
 
3
][MgAl
 
5
][(OH)
 
3
|OH|(BO
 
3
)
 
3
|Si
 
6
O
 
18
]
61.3.1.7Buergerite
[Na][Fe
3+
3
][Al
 
6
][O
 
3
|F|(BO
 
3
)
 
3
|Si
 
6
O
 
18
]
61.3.1.8Povondraite
[Na][Fe
3+
3
][Fe
3+
4
Mg
 
2
][(OH)
 
3
|F|(BO
 
3
)
 
3
|Si
 
6
O
 
18
]
61.3.1.9Olenite
(Na,[ ])[(Al,Li)
 
3
][Al
 
6
][(O,OH)
 
3
|OH|(BO
 
3
)
 
3
|Si
 
6
O
 
18
]
61.3.1.10Elbaite
[Na][(Li,Al)
 
3
][Al
 
6
][(OH)
 
3
|OH|(BO
 
3
)
 
3
|Si
 
6
O
 
18
]
61.3.1.12Schorl
[Na][Fe
2+
3
][Al
 
6
][(OH)
 
3
|OH|(BO
 
3
)
 
3
|Si
 
6
O
 
18
]
61.3.1.13Chromdravite
[Na][Mg
 
3
][(Cr
3+
 
,Fe
3+
 
)
 
6
][(OH)
 
3
|OH|(BO
 
3
)
 
3
|Si
 
6
O
 
18
]
61.3.1.14Vanadiumdravite
[Na][Mg
 
3
][V
3+
6
][(OH)
 
3
|OH|(BO
 
3
)
 
3
|Si
 
6
O
 
18
]

Other Names for Dravite

Synonyms:
CoroniteCoronite (of Hunt)GouverneuriteMg-Turmalin
Other Languages:
German:Coronit
Dravit
Gouvernerit
Gouverneurit
Russian:Дравит
Spanish:Coronita
Dravita
Gouverneurita
Varieties:
Chromian DraviteLime-DraviteSoda-Dravite

Other Information

Electrical:Pyroelectric, piezoelectric
Health Warning: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.

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.

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. (2001b) Ein hell-blauer Olenit-Schörl-Dravit Mischkristall von Ebersdorf, Niederösterreich: Strukturanalyse und Chemie. Mitt. Österr. Mineral. Ges.: 146: 75-77. (in German)

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

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]

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    Localities for Dravite

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    Copyright © Jolyon Ralph and Ida Chau 1993-2009. Site Map. Locality, mineral & photograph data are the copyright of the individuals who submitted them.Further information contact the Site hosted & developed by Jolyon Ralph. Mindat.org is an online information resource dedicated to providing free mineralogical information to all. Mindat relies on the contributions of hundreds of members and supporters. If you would like to add information to improve the quality of our database, then click here to register. Current server date and time: 27th Oct 2009 03:01:59