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Oxy-chromium-dravite

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Formula:
Na(Cr)3(Cr4Mg2)(Si6O18)(BO3)3(OH)3O
Colour:
Emerald green
Lustre:
Vitreous
Hardness:
Specific Gravity:
3.299 (Calculated)
Crystal System:
Trigonal
Name:
For the mineral dravite and its oxygen and chromium contents.
The Cr analogue of vanadio-oxy-chromium-dravite. Oxy-chromium-dravite is related to chromium-dravite by the heterovalent substitution Cr3++O2− → Mg2++OH1−.


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Classification of Oxy-chromium-draviteHide

Approved
Approval Year:
2012

Physical Properties of Oxy-chromium-draviteHide

Vitreous
Transparency:
Transparent
Colour:
Emerald green
Streak:
Green
Hardness:
7½ on Mohs scale
Hardness:
VHN50=14540 kg/mm2 - Vickers
Comment:
Approximately 7½
Fracture:
Conchoidal
Density:
3.299 g/cm3 (Calculated)

Optical Data of Oxy-chromium-draviteHide

Type:
Uniaxial (-)
RI values:
nω = 1.765() nε = 1.715(6)
Max Birefringence:
δ = 0.050
Image shows birefringence interference colour range (at 30µm thickness)
and does not take into account mineral colouration.
Surface Relief:
High
Pleochroism:
Visible
Comments:
pleochroic (O = dark green, E = yellow green) (in plane-polarized light)

Chemical Properties of Oxy-chromium-draviteHide

Formula:
Na(Cr)3(Cr4Mg2)(Si6O18)(BO3)3(OH)3O
IMA Formula:
NaCr3(Cr4Mg2)(Si6O18)(BO3)3(OH)3O

Crystallography of Oxy-chromium-draviteHide

Crystal System:
Trigonal
Class (H-M):
3m - Ditrigonal Pyramidal
Space Group:
R3m
Setting:
R3m
Cell Parameters:
a = 16.1121(3) Å, c = 7.3701(1) Å
Ratio:
a:c = 1 : 0.457
Unit Cell V:
1656.95 ų
Z:
3

X-Ray Powder DiffractionHide

Powder Diffraction Data:
d-spacingIntensity
6.480 (62)
4.634 (24)
4.270 (44)
4.014 (63)
3.542 (50)
3.005 (60)
2.600 (100)
2.063 (47)

Type Occurrence of Oxy-chromium-draviteHide

General Appearance of Type Material:
elongated prisms terminated by a prominent pedion and small, minor pyramidal faces
Place of Conservation of Type Material:
Museum of Mineralogy, Earth Sciences Department, Sapienza University of Rome, Rome, Italy, catalogue number 33064
Geological Setting of Type Material:
chromphyllite-bearing quartzite and banded quartz-diopside rock
Associated Minerals at Type Locality:

Synonyms of Oxy-chromium-draviteHide

Relationship of Oxy-chromium-dravite to other SpeciesHide

Other Members of this group:
AdachiiteCaFe3Al6(Si5AlO18)(BO3)3(OH)3(OH)Trig. 3m : R3m
BosiiteNaFe3+3(Al4Mg2)(Si6O18)(BO3)3(OH)3OTrig. 3m : R3m
Chromium-draviteNa(Mg3)Cr3+6(Si6O18)(BO3)3(OH)3(OH)Trig.
Chromo-alumino-povondraiteNa(Cr3)(Al4Mg2)(Si6O18)(BO3)3(OH)3OTrig. 3m : R3m
DarrellhenryiteNa(LiAl2)Al6(BO3)3Si6O18(OH)3O Trig. 3m : R3m
DraviteNa(Mg3)Al6(Si6O18)(BO3)3(OH)3(OH)Trig. 3m : R3m
ElbaiteNa(Li1.5Al1.5)Al6(Si6O18)(BO3)3(OH)3(OH)Trig. 3m : R3m
FeruviteCa(Fe2+)3MgAl5(Si6O18)(BO3)3(OH)3(OH)Trig. 3m : R3m
Fluor-buergeriteNa(Fe3+3)Al6(Si6O18)(BO3)3O3FTrig. 3m : R3m
Fluor-draviteNa(Mg3)Al6(Si6O18)(BO3)3(OH)3FTrig. 3m : R3m
Fluor-elbaiteNa(Li1.5Al1.5)Al6(Si6O18)(BO3)3(OH)3FTrig. 3m : R3m
Fluor-feruviteCa(Fe2+)3MgAl5(Si6O18)(BO3)3(OH)3F
Fluor-liddicoatiteCa(Li2Al)Al6(Si6O18)(BO3)3(OH)3FTrig. 3m : R3m
Fluor-schorlNa(Fe2+3)Al6(Si6O18)(BO3)3(OH)3FTrig. 3m : R3m
Fluor-tsilaisiteNa(Mn2+)3Al6(Si6O18)(BO3)3(OH)3FTrig. 3m : R3m
Fluor-uviteCa(Mg3)MgAl5(Si6O18)(BO3)3(OH)3FTrig. 3m : R3m
Foitite(□,Na)(Fe2+2Al)Al6(Si6O18)(BO3)3(OH)3OHTrig. 3m : R3m
LiddicoatiteCa(Li2Al)Al6(Si6O18)(BO3)3(OH)3(OH)Trig. 3m : R3m
LucchesiiteCaFe2+3 Al6(Si6O18)(BO3)3(OH)3OTrig. 3m : R3m
Luinaite-(OH)Na(Fe2+)3Al6(Si6O18)(BO3)3(OH)3(OH)Mon. m : Bm
Magnesio-foitite(□,Na)(Mg2Al)Al6(Si6O18)(BO3)3(OH)3(OH)Trig.
MaruyamaiteK(MgAl2)(Al5Mg)(BO3)3(Si6O18)(OH)3OTrig. 3m : R3m
OleniteNa(Al3)Al6(Si6O18)(BO3)3O3(OH)Trig.
Oxy-draviteNa(MgAl2)MgAl5(Si6O18)(BO3)3(OH)3OTrig. 3m : R3m
Oxy-foitite□(Fe2+Al2)Al6(Si6O18)(BO3)3(OH)3OTrig. 3m (3 2/m) : R3m
Oxy-rossmanite☐(LiAl2)Al6(Si6O18)(BO3)3(OH)3O
Oxy-schorlNa(Fe2+2Al)Al6(Si6O18)(BO3)3(OH)3OTrig. 3m : R3m
Oxy-uviteCaMg3Al6(Si6O18)(BO3)3(OH)3O
Oxy-vanadium-draviteNa(V)3(V4Mg2)Si6O18(BO3)3(OH)3OTrig. 3m : R3m
PovondraiteNaFe3+3(Mg2Fe3+4)(Si6O18)(BO3)3(OH)3OTrig.
Rossmanite☐(LiAl2)Al6(Si6O18)(BO3)3(OH)3(OH)Trig. 3m : R3m
SchorlNa(Fe2+3)Al6(Si6O18)(BO3)3(OH)3(OH)Trig. 3m : R3m
TsilaisiteNa(Mn2+)3Al6(Si6O18)(BO3)3(OH)3(OH)Trig. 3m : R3m
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)
Uvite SeriesCa(Mg3)MgAl5(Si6O18)(BO3)3(OH)3(F/OH)Trig. 3m : R3m
Vanadio-oxy-chromium-draviteNa(V)3(Cr4Mg2)(Si6O18)(BO3)3(OH)3O Trig. 3m : R3m
Vanadio-oxy-draviteNaV3(Al4Mg2)(Si6O18)(BO3)3(OH)3OTrig. 3m

Common AssociatesHide

CalciteCaCO3
Chromian PhlogopiteK(Mg,Cr)3(AlSi3O10)(OH)2
ChromiteFe2+Cr3+2O4
ChromphylliteK(Cr,Al)2(AlSi3O10)(OH,F)2
Diopside-Kosmochlor Series
EskolaiteCr2O3
PyriteFeS2
QuartzSiO2
RutileTiO2
TitaniteCaTi(SiO4)O
Tremolite☐{Ca2}{Mg5}(Si8O22)(OH)2
UvaroviteCa3Cr2(SiO4)3

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.

References for Oxy-chromium-draviteHide

Reference List:
Sort by Year (asc) | by Year (desc) | by Author (A-Z) | by Author (Z-A)
Bosi, F., Rezeniskii, L. and Skogby, H. (2012) Oxy-chromium-dravite, IMA 2011-097. CNMNC Newsletter, 13(6), 808. Mineralogical Magazine, 76, 807-817.
Bosi, F., Reznitskii, L., Skogby, H. (2012): Oxy-chromium-dravite, NaCr3(Cr4Mg2)(Si6O18)(BO3)3(OH)3O, a new mineral species of the tourmaline supergroup. American Mineralogist, 97, 2024-2030
Vereshchagin, O. S., Rozhdestvenskaya, I. V., Frank-Kamenetskaya, O. V., Zolotarev, A. A. (2014): Ion substitutions and structural adjustment in Cr-bearing tourmalines. European Journal of Mineralogy 26, 309-321.

Internet Links for Oxy-chromium-draviteHide

Localities for Oxy-chromium-draviteHide

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.

Locality ListHide

- This locality has map coordinates listed. - This locality has estimated coordinates. ⓘ - Click for 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 (eg from pseudomorphs.)

All localities listed without proper references should be considered as questionable.
Russia (TL)
 
  • Eastern-Siberian Region
    • Prebaikalia (Pribaikal'e)
      • Irkutskaya Oblast'
        • Lake Baikal area
          • Slyudyanka (Sludyanka)
Bosi, F., Rezeniskii, L. and Skogby, H. (2012) Oxy-chromium-dravite, IMA 2011-097. CNMNC Newsletter, 13(6), 808. Mineralogical Magazine, 76, 807-817.; Reznitskii, L., Clark, C. M., Hawthorne, F. C., Grice, J. D., Skogby, H., Hålenius, U., & Bosi, F. (2014). Chromo-alumino-povondraite, NaCr3 (Al4Mg2)(Si6O18)(BO3) 3 (OH) 3O, a new mineral species of the tourmaline supergroup. American Mineralogist, 99(8-9), 1767-1773.
Mineral and/or Locality  
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