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Chromium-dravite

A valid IMA mineral species
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About Chromium-draviteHide

Formula:
NaMg3Cr3+6(Si6O18)(BO3)3(OH)3(OH)
Colour:
Dark emerald-green to greenish-black.
Lustre:
Vitreous, Resinous
Hardness:
7 - 7½
Crystal System:
Trigonal
Name:
For being the chromium analogue of dravite.
Tourmaline Group. The Cr3+ analogue of Dravite.

Originally named chromdravite (Rumantseva, 1983).

A detailed study by Vereshchagin et al. (2010) and Rozhdestvenskaya et al. (2011) strongly suggests that the "ideal" formula of chromdravite, NaMg3Cr6(BO3)3(Si6O18)(OH)4, is not realistic and should in fact be Na(Cr2Mg)(Cr4Mg2)(BO3)3(Si6O18)(OH)4 (Cr-Mg disorder on both Y and Z sites, leading to a more stable structure.)


Unique IdentifiersHide

Mindat ID:
1031
Long-form identifier:
mindat:1:1:1031:9

IMA Classification of Chromium-draviteHide

Approved
IMA status notes:
Published without approval
IMA Formula:
NaMg3Cr3+6(Si6O18)(BO3)3(OH)3OH
Approval history:
Published without approval: 2009

Classification of Chromium-draviteHide

9.CK.05

9 : SILICATES (Germanates)
C : Cyclosilicates
K : [Si6O18]12- 6-membered single rings, with insular complex anions
Dana 7th ed.:
61.3.1.13
61.3.1.11

61 : CYCLOSILICATES Six-Membered Rings
3 : Six-Membered Rings with borate groups
17.5.37

17 : Silicates Containing other Anions
5 : Borosilicates

Mineral SymbolsHide

As of 2021 there are now IMA–CNMNC approved mineral symbols (abbreviations) for each mineral species, useful for tables and diagrams.

SymbolSourceReference for Standard
CdrvIMA–CNMNCWarr, L.N. (2021). IMA–CNMNC approved mineral symbols. Mineralogical Magazine, 85(3), 291-320. doi:10.1180/mgm.2021.43

Physical Properties of Chromium-draviteHide

Vitreous, Resinous
Colour:
Dark emerald-green to greenish-black.
Streak:
Greyish-green.
Hardness:
7 - 7½ on Mohs scale

Optical Data of Chromium-draviteHide

Type:
Uniaxial (-)
RI values:
nω = 1.778 nε = 1.772
Max. Birefringence:
δ = 0.006
Based on recorded range of RI values above.

Interference Colours:
The colours simulate birefringence patterns seen in thin section under crossed polars. They do not take into account mineral colouration or opacity.

Michel-Levy Bar The default colours simulate the birefringence range for a 30 µm thin-section thickness. Adjust the slider to simulate a different thickness.

Grain Simulation You can rotate the grain simulation to show how this range might look as you rotated a sample under crossed polars. Each grain retains its interference colour (retardation) while its brightness falls to black at extinction and reaches a maximum between extinction positions.

Surface Relief:
Moderate

Chemistry of Chromium-draviteHide

Mindat Formula:
NaMg3Cr3+6(Si6O18)(BO3)3(OH)3(OH)
Element Weights:
Element% weight
O44.730 %
Cr28.135 %
Si15.197 %
Mg6.576 %
B2.925 %
Na2.073 %
H0.364 %

Calculated from ideal end-member formula.
Common Impurities:
Mn,Ti,V,Al,V,Ca

Crystallography of Chromium-draviteHide

Crystal System:
Trigonal
Class (H-M):
3m - Ditrigonal Pyramidal
Space Group:
R3m
Cell Parameters:
a = 16.11 Å, c = 7.27 Å
Ratio:
a:c = 1 : 0.451
Unit Cell V:
1,634.02 ų (Calculated from Unit Cell)
Z:
3

Geological EnvironmentHide

Paragenetic Mode(s):

Type Occurrence of Chromium-draviteHide

Synonyms of Chromium-draviteHide

Other Language Names for Chromium-draviteHide

Simplified Chinese:铬镁电气石
Spanish:Cromdravita
Traditional Chinese:鉻鎂電氣石

Relationship of Chromium-dravite to other SpeciesHide

Other Members of Tourmaline:
AdachiiteCaFe3Al6(Si5AlO18)(BO3)3(OH)3(OH)Trig. 3m : R3m
Alumino-oxy-rossmanite◻Al3Al6(Si5AlO18)(BO3)3(OH)3OTrig. 3m : R3m
BosiiteNaFe3+3(Al4Mg2)(Si6O18)(BO3)3(OH)3OTrig. 3m : R3m
Celleriite◻(Mn2+2Al)Al6(Si6O18)(BO3)3(OH)3(OH)Trig. 3m : R3m
Chromo-alumino-povondraiteNaCr3(Al4Mg2)(Si6O18)(BO3)3(OH)3OTrig. 3m : R3m
DarrellhenryiteNa(Al2Li)Al6(Si6O18)(BO3)3(OH)3OTrig. 3m : R3m
DraviteNaMg3Al6(Si6O18)(BO3)3(OH)3(OH)Trig. 3m : R3m
DutrowiteNa(Fe2+2.5Ti0.5)Al6(Si6O18)(BO3)3(OH)3OTrig. 3m : R3m
ElbaiteNa(Li1.5Al1.5)Al6(Si6O18)(BO3)3(OH)3(OH)Trig. 3m : R3m
ErtliteNaAl3Al6(Si4B2O18)(BO3)3(OH)3OTrig. 3m : R3m
Ferro-bosiiteNaFe3+3(Al4Fe2+2)(Si6O18)(BO3)3(OH)3OTrig. 3m : R3m
FeruviteCaFe2+3(Al5Mg)(Si6O18)(BO3)3(OH)3(OH)Trig. 3m : R3m
Fluor-buergeriteNaFe3+3Al6(Si6O18)(BO3)3O3FTrig. 3m : R3m
Fluor-draviteNaMg3Al6(Si6O18)(BO3)3(OH)3FTrig. 3m : R3m
Fluor-elbaiteNa(Li1.5Al1.5)Al6(Si6O18)(BO3)3(OH)3FTrig. 3m : R3m
Fluor-liddicoatiteCa(Li2Al)Al6(Si6O18)(BO3)3(OH)3FTrig. 3m : R3m
Fluor-rossmanite◻(Al2Li)Al6(Si6O18)(BO3)3(OH)3FTrig. 3m(32/m) : R3m
Fluor-schorlNaFe2+3Al6(Si6O18)(BO3)3(OH)3FTrig. 3m : R3m
Fluor-tsilaisiteNaMn2+3Al6(Si6O18)(BO3)3(OH)3FTrig. 3m : R3m
Fluor-uviteCaMg3(Al5Mg)(Si6O18)(BO3)3(OH)3FTrig. 3m : R3m
Foitite◻(Fe2+2Al)Al6(Si6O18)(BO3)3(OH)3(OH)Trig. 3m : R3m
LiddicoatiteCa(Li2Al)Al6(Si6O18)(BO3)3(OH)3(OH)Trig. 3m : R3m
LucchesiiteCaFe2+3 Al6(Si6O18)(BO3)3(OH)3OTrig. 3m : R3m
Magnesio-dutrowiteNa(Mg2.5Ti0.5)Al6(Si6O18)(BO3)3(OH)3OTrig. 3m : R3m
Magnesio-foitite◻(Mg2Al)Al6(Si6O18)(BO3)3(OH)3(OH)Trig. 3m : R3m
Magnesio-lucchesiiteCaMg3Al6(Si6O18)(BO3)3(OH)3OTrig. 3m : R3m
MaruyamaiteK(Al2Mg)(Al5Mg)(Si6O18)(BO3)3(OH)3OTrig. 3m : R3m
OleniteNaAl3Al6(Si6O18)(BO3)3O3(OH)Trig. 3m : R3m
Oxy-chromium-draviteNaCr3(Cr4Mg2)(Si6O18)(BO3)3(OH)3O Trig. 3m : R3m
Oxy-draviteNa(Al2Mg)(Al5Mg)(Si6O18)(BO3)3(OH)3OTrig. 3m : R3m
Oxy-foitite◻(Fe2+Al2)Al6(Si6O18)(BO3)3(OH)3OTrig. 3m(32/m) : R3m
Oxy-schorlNa(Fe2+2Al)Al6(Si6O18)(BO3)3(OH)3OTrig. 3m : R3m
Oxy-vanadium-draviteNaV3(V4Mg2)(Si6O18)(BO3)3(OH)3OTrig. 3m : R3m
PovondraiteNaFe3+3(Mg2Fe3+4)(Si6O18)(BO3)3(OH)3OTrig. 3m : R3m
PrincivalleiteNa(Mn2Al)Al6(Si6O18)(BO3)3(OH)3OTrig. 3m : R3m
Rossmanite◻(LiAl2)Al6(Si6O18)(BO3)3(OH)3(OH)Trig. 3m : R3m
SchorlNaFe2+3Al6(Si6O18)(BO3)3(OH)3(OH)Trig. 3m : R3m
TsilaisiteNaMn2+3Al6(Si6O18)(BO3)3(OH)3(OH)Trig. 3m : R3m
'UM2000-64-SiO:BFeHKMg'(K,Na)Fe3+3(Mg2Fe3+4)Si6O18(BO3)3(OH)3O
'UM2008-52-SiO:AlBCaFFeHLiMgNa'(Ca,Na,◻)(Al,Li,Fe,Mg)3Al6[Si6O18](BO3)3(OH,O)3(F,O)
'Unnamed (F analogue of feruvite)'CaFe2+3(Al5Mg)(Si6O18)(BO3)3(OH)3F
'Unnamed (Mn2+-F-analogue of foitite)'◻(Mn2+2Al)Al6(Si6O18)(BO3)3(OH)3F ?
'Unnamed (Pb-analogue of Fluor-liddicoatite)'Pb(Li2Al)Al6(Si6O18)(BO3)3(OH)3F
UviteCaMg3(Al5Mg)(Si6O18)(BO3)3(OH)3(OH)Trig. 3m : R3m
Vanadio-oxy-chromium-draviteNaV3(Cr4Mg2)(Si6O18)(BO3)3(OH)3O Trig. 3m : R3m
Vanadio-oxy-draviteNaV3(Al4Mg2)(Si6O18)(BO3)3(OH)3OTrig. 3m : R3m

Common AssociatesHide

Associations Based on Photo Data:
1 photo of Chromium-dravite associated with CalciteCaCO3

Related Minerals - Strunz-mindat GroupingHide

9.CK.AdachiiteCaFe3Al6(Si5AlO18)(BO3)3(OH)3(OH)Trig. 3m : R3m
9.CK.Magnesio-dutrowiteNa(Mg2.5Ti0.5)Al6(Si6O18)(BO3)3(OH)3OTrig. 3m : R3m
9.CK.DarrellhenryiteNa(Al2Li)Al6(Si6O18)(BO3)3(OH)3OTrig. 3m : R3m
9.CK.Fluor-schorlNaFe2+3Al6(Si6O18)(BO3)3(OH)3FTrig. 3m : R3m
9.CK.PrincivalleiteNa(Mn2Al)Al6(Si6O18)(BO3)3(OH)3OTrig. 3m : R3m
9.CK.Alumino-oxy-rossmanite◻Al3Al6(Si5AlO18)(BO3)3(OH)3OTrig. 3m : R3m
9.CK.DutrowiteNa(Fe2+2.5Ti0.5)Al6(Si6O18)(BO3)3(OH)3OTrig. 3m : R3m
9.CK.Ferro-bosiiteNaFe3+3(Al4Fe2+2)(Si6O18)(BO3)3(OH)3OTrig. 3m : R3m
9.CK.BosiiteNaFe3+3(Al4Mg2)(Si6O18)(BO3)3(OH)3OTrig. 3m : R3m
9.CK.Celleriite◻(Mn2+2Al)Al6(Si6O18)(BO3)3(OH)3(OH)Trig. 3m : R3m
9.CK.05FeruviteCaFe2+3(Al5Mg)(Si6O18)(BO3)3(OH)3(OH)Trig. 3m : R3m
9.CK.05Fluor-rossmanite◻(Al2Li)Al6(Si6O18)(BO3)3(OH)3FTrig. 3m(32/m) : R3m
9.CK.05Oxy-schorlNa(Fe2+2Al)Al6(Si6O18)(BO3)3(OH)3OTrig. 3m : R3m
9.CK.05Fluor-elbaiteNa(Li1.5Al1.5)Al6(Si6O18)(BO3)3(OH)3FTrig. 3m : R3m
9.CK.05DraviteNaMg3Al6(Si6O18)(BO3)3(OH)3(OH)Trig. 3m : R3m
9.CK.05Fluor-uviteCaMg3(Al5Mg)(Si6O18)(BO3)3(OH)3FTrig. 3m : R3m
9.CK.05Foitite◻(Fe2+2Al)Al6(Si6O18)(BO3)3(OH)3(OH)Trig. 3m : R3m
9.CK.05Vanadio-oxy-draviteNaV3(Al4Mg2)(Si6O18)(BO3)3(OH)3OTrig. 3m : R3m
9.CK.05Fluor-buergeriteNaFe3+3Al6(Si6O18)(BO3)3O3FTrig. 3m : R3m
9.CK.05'Unnamed (F analogue of feruvite)'CaFe2+3(Al5Mg)(Si6O18)(BO3)3(OH)3F
9.CK.05ErtliteNaAl3Al6(Si4B2O18)(BO3)3(OH)3OTrig. 3m : R3m
9.CK.05TsilaisiteNaMn2+3Al6(Si6O18)(BO3)3(OH)3(OH)Trig. 3m : R3m
9.CK.05Fluor-liddicoatiteCa(Li2Al)Al6(Si6O18)(BO3)3(OH)3FTrig. 3m : R3m
9.CK.05UviteCaMg3(Al5Mg)(Si6O18)(BO3)3(OH)3(OH)Trig. 3m : R3m
9.CK.05ElbaiteNa(Li1.5Al1.5)Al6(Si6O18)(BO3)3(OH)3(OH)Trig. 3m : R3m
9.CK.05Fluor-tsilaisiteNaMn2+3Al6(Si6O18)(BO3)3(OH)3FTrig. 3m : R3m
9.CK.05Oxy-foitite◻(Fe2+Al2)Al6(Si6O18)(BO3)3(OH)3OTrig. 3m(32/m) : R3m
9.CK.05LiddicoatiteCa(Li2Al)Al6(Si6O18)(BO3)3(OH)3(OH)Trig. 3m : R3m
9.CK.05Vanadio-oxy-chromium-draviteNaV3(Cr4Mg2)(Si6O18)(BO3)3(OH)3O Trig. 3m : R3m
9.CK.05Rossmanite◻(LiAl2)Al6(Si6O18)(BO3)3(OH)3(OH)Trig. 3m : R3m
9.CK.05Oxy-vanadium-draviteNaV3(V4Mg2)(Si6O18)(BO3)3(OH)3OTrig. 3m : R3m
9.CK.05OleniteNaAl3Al6(Si6O18)(BO3)3O3(OH)Trig. 3m : R3m
9.CK.05'UM2000-64-SiO:BFeHKMg'(K,Na)Fe3+3(Mg2Fe3+4)Si6O18(BO3)3(OH)3O
9.CK.05Magnesio-lucchesiiteCaMg3Al6(Si6O18)(BO3)3(OH)3OTrig. 3m : R3m
9.CK.05PovondraiteNaFe3+3(Mg2Fe3+4)(Si6O18)(BO3)3(OH)3OTrig. 3m : R3m
9.CK.05LucchesiiteCaFe2+3 Al6(Si6O18)(BO3)3(OH)3OTrig. 3m : R3m
9.CK.05Chromo-alumino-povondraiteNaCr3(Al4Mg2)(Si6O18)(BO3)3(OH)3OTrig. 3m : R3m
9.CK.05Fluor-draviteNaMg3Al6(Si6O18)(BO3)3(OH)3FTrig. 3m : R3m
9.CK.05Oxy-draviteNa(Al2Mg)(Al5Mg)(Si6O18)(BO3)3(OH)3OTrig. 3m : R3m
9.CK.05Oxy-chromium-draviteNaCr3(Cr4Mg2)(Si6O18)(BO3)3(OH)3O Trig. 3m : R3m
9.CK.05'Luinaite-(OH)'NaFe2+3Al6(Si6O18)(BO3)3(OH)3(OH)Mon. m : Bm
9.CK.05SchorlNaFe2+3Al6(Si6O18)(BO3)3(OH)3(OH)Trig. 3m : R3m
9.CK.05Magnesio-foitite◻(Mg2Al)Al6(Si6O18)(BO3)3(OH)3(OH)Trig. 3m : R3m
9.CK.05MaruyamaiteK(Al2Mg)(Al5Mg)(Si6O18)(BO3)3(OH)3OTrig. 3m : R3m
9.CK.10Abenakiite-(Ce)Na26Ce6(Si6O18)(PO4)6(CO3)6(SO2)OTrig. 3 : R3
9.CK.15ScawtiteCa7(Si3O9)2CO3 · 2H2OMon. 2/m
9.CK.20Thorosteenstrupine(Ca,Th,Mn)3Si4O11F · 6H2O
9.CK.20Steenstrupine-(Ce)Na14Mn2+2Fe3+2Ce6Zr(Si6O18)2(PO4)6(PO3OH)(OH)2 · 2H2OTrig. 3m(32/m) : R3m

Other InformationHide

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

Internet Links for Chromium-draviteHide

References for Chromium-draviteHide

Reference List:

Localities for Chromium-draviteHide

Showing 9 localities.

This 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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Locality ListHide

- This locality has map coordinates listed. - This locality has estimated coordinates. ⓘ - Click for references and further information on this occurrence. ? - Indicates mineral may be doubtful at this locality. - Good crystals or important locality for species. - World class for species or very significant. (TL) - Type Locality for a valid mineral species. (FRL) - First Recorded Locality for everything else (eg varieties). Struck out - Mineral was erroneously reported from this locality. Faded * - Never found at this locality but inferred to have existed at some point in the past (e.g. from pseudomorphs).

All localities listed without proper references should be considered as questionable.
Brazil
 
  • Minas Gerais
    • Coronel Murta
erroneously reported [MinRec 33:209]
Canada
 
  • Québec
    • Nord-du-Québec
      • Jamésie
        • Baie-James
          • Otish Mountains
Alexandre et al. (2014)
Finland
 
  • North Savo
    • Kaavi
...
India
 
  • Odisha
    • Keonjhar District
- (see explanation under chromoaluminopovondraite)
Pakistan
 
  • Khyber Pakhtunkhwa Province
    • Swat District
- (2002)
Russia
 
  • Irkutsk Oblast
    • Slyudyansky District
      • Slyudyanka
        • Pokhabikha River Valley
Pekov (1998)
  • Republic of Karelia
    • Medvezhyegorsky District
      • Zaonezhie peninsula
Jeff Weissman collection (purchased from Excalibur Mineral Company)
Pekov (1998)
USA
 
  • New York
    • St. Lawrence County
      • Fowler
        • Balmat
Marian Lupulescu (New York State Museum)
 
and/or  
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