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Chromdravite

Big Photo

Onega trough, Karelia Republic, Northern Region, Russia
© 2007, J. Weissman

Formula:
[Na][Mg
 
3
][(Cr
3+
 
,Fe
3+
 
)
 
6
][(OH)
 
3
|OH|(BO
 
3
)
 
3
|Si
 
6
O
 
18
]
System:TrigonalColour:Dark emerald-green to ...
Lustre:Vitreous, ResinousHardness:7 - 7½


Tourmaline Group. The Cr3+ analogue of Dravite.

Classification of Chromdravite

IMA status:Approved
Strunz 8th edition ID:8/E.19-30
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:61.3.1.13
Dana 8th edition ID:61.3.1.11

61 : CYCLOSILICATES Six-Membered Rings
3 : Six-Membered Rings with borate groups
Hey's CIM Ref.:17.5.37

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

Type Locality:Onega trough, Karelia Republic, Northern Region, Russia
Year of Discovery:1983

Physical Properties of Chromdravite

Lustre:Vitreous, Resinous
Colour:Dark emerald-green to greenish-black.
Streak:Greyish-green.
Hardness (Mohs):7 - 7½

Crystallography of Chromdravite

Crystal System:Trigonal
Cell Parameters:a = 16.11Å, c = 7.27Å
Ratio:a:c = 1 : 0.451
Unit Cell Volume:V 1,634.02 ų (Calculated from Unit Cell)

Optical Data of Chromdravite

Type:Uniaxial (-)
RI values: nω = 1.778 nε = 1.772
Maximum Birefringence:δ = 0.006

Chart shows birefringence interference colour range (at 30µm thickness) and does not take into account mineral colouration.
Surface Relief:Very High

Chemical Properties of Chromdravite

Formula:
[Na][Mg
 
3
][(Cr
3+
 
,Fe
3+
 
)
 
6
][(OH)
 
3
|OH|(BO
 
3
)
 
3
|Si
 
6
O
 
18
]
Essential elements:B, Cr, H, Mg, Na, O, Si
All elements listed in formula:B, Cr, Fe, H, Mg, Na, O, Si
Common Impurities:Mn,Ti,V,Al,V,Ca

Relationship of Chromdravite to other Species

Member of:Tourmaline Group
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.05Dravite
[Na][Mg
 
3
][Al
 
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+
6
][O
 
3
|OH|(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
Ca[BSiO
 
4
]
 
2
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
(Ca,Y)
 
2
(Ti
4+
 
,Fe
3+
 
,Al)[B
 
4
Si
 
4
O
 
22
(O,OH)
 
6
](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
]
17.5.27Dravite
[Na][Mg
 
3
][Al
 
6
][(OH)
 
3
|OH|(BO
 
3
)
 
3
|Si
 
6
O
 
18
]
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
Na
 
2
BaMnTiB
 
2
Si
 
6
O
 
20
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
17.5.38Wawayandaite
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
(Ca,Fe,Mn)Al
 
2
BSi
 
4
O
 
15
OH
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+
6
][O
 
3
|OH|(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
]
61.3.1.11Dravite
[Na][Mg
 
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
]
61.3.1.14Vanadiumdravite
[Na][Mg
 
3
][V
3+
6
][(OH)
 
3
|OH|(BO
 
3
)
 
3
|Si
 
6
O
 
18
]

Other Names for Chromdravite

Synonyms:
Chromium-DraviteIMA1982-055
German names:
Chromdravit
Russian names:
Хромдравит
Spanish names:
Chromdravita

Other Information

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 Chromdravite

Reference List:American Mineralogist (1984): 69: 210.

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

Internet Links for Chromdravite

Search Engines:
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  • Look for Chromdravite images on Google
    • External Links:
  • Look for Chromdravite on Webmineral
  • Look for Chromdravite on Athena Mineralogy
  • Look for Chromdravite on Wikipedia
  • Look for Chromdravite on Mineralien Atlas
  • Raman and XRD data at RRUFF project
  • American Mineralogist Crystal Structure Database
  • Search for Chromdravite in the Natural History Museum (London) online catalogue
  • Chromdravite details from Handbook of Mineralogy (PDF)
    • Mineral Dealers:
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    • Localities for Chromdravite

    (TL) indicates type locality. ? indicates mineral may be doubtful at this locality. All other localities listed without reference should be considered as uncertain and unproven until references can be found.
    Brazil
     
    • Southeast Region
      • Minas Gerais
        • Coronel Murta
          • Barra de Salinas
    		[MinRec 33:209]
    Finland
     
    • Itä-Suomen Lääni
      • Outokumpu
    Pakistan
     
    • North-West Frontier Province
      • Malakand Region
        • Swat District (Swat Valley)
    		[Emeralds of the World - p24 English extraLapis Vol2 2002]
    Russia
     
    • Eastern-Siberian Region
      • Transbaikalia (Zabaykalye)
        • Buriatia (Buryatia) Republic
          • Baikal area
            • Sludyanka (Slyudyanka)
              • Pokhabikha River Valley
    • Northern Region
      • Karelia Republic
    Mineral and/or Locality
    Google
     
    www.mindat.org Web
    Copyright © Jolyon & Ida Ralph 1993-2008. 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. Mineral Specimens available here.