Chromium-dravite
A material that is NOT an approved mineral species
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About Chromium-dravite
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
Member of:
Name:
For being the chromium analogue of dravite.
First Recorded Locality:
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.)
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 Identifiers
Mindat ID:
1031
Long-form identifier:
mindat:1:1:1031:9
GUID
(UUID V4):
(UUID V4):
357611f8-7db2-47c3-a2b7-7a66d6a757ec
IMA Classification of Chromium-dravite
IMA status notes:
Published without approval
Approval history:
Published without approval: 2009
Classification of Chromium-dravite
9.CK.05
9 : SILICATES (Germanates)
C : Cyclosilicates
K : [Si6O18]12- 6-membered single rings, with insular complex anions
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
61 : CYCLOSILICATES Six-Membered Rings
3 : Six-Membered Rings with borate groups
17.5.37
17 : Silicates Containing other Anions
5 : Borosilicates
17 : Silicates Containing other Anions
5 : Borosilicates
Mineral Symbols
As of 2021 there are now IMA–CNMNC approved mineral symbols (abbreviations) for each mineral species, useful for tables and diagrams.
Symbol | Source | Reference |
---|---|---|
Cdrv | IMA–CNMNC | Warr, L.N. (2021). IMA–CNMNC approved mineral symbols. Mineralogical Magazine, 85(3), 291-320. doi:10.1180/mgm.2021.43 |
Physical Properties of Chromium-dravite
Vitreous, Resinous
Colour:
Dark emerald-green to greenish-black.
Streak:
Greyish-green.
Hardness:
7 - 7½ on Mohs scale
Optical Data of Chromium-dravite
Type:
Uniaxial (-)
RI values:
nω = 1.778 nε = 1.772
Max Birefringence:
δ = 0.006
Image shows birefringence interference colour range (at 30µm thickness)
and does not take into account mineral colouration.
and does not take into account mineral colouration.
Surface Relief:
Very High
Chemistry of Chromium-dravite
Mindat Formula:
NaMg3Cr3+6(Si6O18)(BO3)3(OH)3(OH)
Common Impurities:
Mn,Ti,V,Al,V,Ca
Crystallography of Chromium-dravite
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 Environment
Paragenetic Mode(s):
Paragenetic Mode | Earliest Age (Ga) |
---|---|
Near-surface Processes | |
23 : Subaerial aqueous alteration by non-redox-sensitive fluids (see also #47) | |
High-𝑇 alteration and/or metamorphism | |
31 : Thermally altered carbonate, phosphate, and iron formations |
First Recorded Occurrence of Chromium-dravite
Synonyms of Chromium-dravite
Other Language Names for Chromium-dravite
German:Chromdravit
Russian:Хромдравит
Simplified Chinese:铬镁电气石
Spanish:Cromdravita
Traditional Chinese:鉻鎂電氣石
Relationship of Chromium-dravite to other Species
Member of:
Other Members of this group:
Adachiite | CaFe3Al6(Si5AlO18)(BO3)3(OH)3(OH) | Trig. 3m : R3m |
Alumino-oxy-rossmanite | ◻Al3Al6(Si5AlO18)(BO3)3(OH)3O | Trig. 3m : R3m |
Bosiite | NaFe3+3(Al4Mg2)(Si6O18)(BO3)3(OH)3O | Trig. 3m : R3m |
Celleriite | ◻(Mn2+2Al)Al6(Si6O18)(BO3)3(OH)3(OH) | Trig. 3m : R3m |
Chromo-alumino-povondraite | NaCr3(Al4Mg2)(Si6O18)(BO3)3(OH)3O | Trig. 3m : R3m |
Darrellhenryite | Na(Al2Li)Al6(Si6O18)(BO3)3(OH)3O | Trig. 3m : R3m |
Dravite | NaMg3Al6(Si6O18)(BO3)3(OH)3(OH) | Trig. 3m : R3m |
Dutrowite | Na(Fe2+2.5Ti0.5)Al6(Si6O18)(BO3)3(OH)3O | Trig. 3m : R3m |
Elbaite | Na(Li1.5Al1.5)Al6(Si6O18)(BO3)3(OH)3(OH) | Trig. 3m : R3m |
Ferro-bosiite | NaFe3+3(Al4Fe2+2)(Si6O18)(BO3)3(OH)3O | Trig. 3m : R3m |
Feruvite | CaFe2+3(Al5Mg)(Si6O18)(BO3)3(OH)3(OH) | Trig. 3m : R3m |
Fluor-buergerite | NaFe3+3Al6(Si6O18)(BO3)3O3F | Trig. 3m : R3m |
Fluor-dravite | NaMg3Al6(Si6O18)(BO3)3(OH)3F | Trig. 3m : R3m |
Fluor-elbaite | Na(Li1.5Al1.5)Al6(Si6O18)(BO3)3(OH)3F | Trig. 3m : R3m |
Fluor-liddicoatite | Ca(Li2Al)Al6(Si6O18)(BO3)3(OH)3F | Trig. 3m : R3m |
Fluor-rossmanite | ◻(Al2Li)Al6(Si6O18)(BO3)3(OH)3F | Trig. 3m (3 2/m) : R3m |
Fluor-schorl | NaFe2+3Al6(Si6O18)(BO3)3(OH)3F | Trig. 3m : R3m |
Fluor-tsilaisite | NaMn2+3Al6(Si6O18)(BO3)3(OH)3F | Trig. 3m : R3m |
Fluor-uvite | CaMg3(Al5Mg)(Si6O18)(BO3)3(OH)3F | Trig. 3m : R3m |
Foitite | ◻(Fe2+2Al)Al6(Si6O18)(BO3)3(OH)3(OH) | Trig. 3m : R3m |
Liddicoatite | Ca(Li2Al)Al6(Si6O18)(BO3)3(OH)3(OH) | Trig. 3m : R3m |
Lucchesiite | CaFe2+3 Al6(Si6O18)(BO3)3(OH)3O | Trig. 3m : R3m |
Magnesio-dutrowite | Na(Mg2.5Ti0.5)Al6(Si6O18)(BO3)3(OH)3O | Trig. 3m : R3m |
Magnesio-foitite | ◻(Mg2Al)Al6(Si6O18)(BO3)3(OH)3(OH) | Trig. 3m : R3m |
Magnesio-lucchesiite | CaMg3Al6(Si6O18)(BO3)3(OH)3O | Trig. 3m : R3m |
Maruyamaite | K(Al2Mg)(Al5Mg)(Si6O18)(BO3)3(OH)3O | Trig. 3m : R3m |
Olenite | NaAl3Al6(Si6O18)(BO3)3O3(OH) | Trig. 3m : R3m |
Oxy-chromium-dravite | NaCr3(Cr4Mg2)(Si6O18)(BO3)3(OH)3O | Trig. 3m : R3m |
Oxy-dravite | Na(Al2Mg)(Al5Mg)(Si6O18)(BO3)3(OH)3O | Trig. 3m : R3m |
Oxy-foitite | ◻(Fe2+Al2)Al6(Si6O18)(BO3)3(OH)3O | Trig. 3m (3 2/m) : R3m |
Oxy-rossmanite | ◻(Li0.5Al2.5)Al6(Si6O18)(BO3)3(OH)3O | |
Oxy-schorl | Na(Fe2+2Al)Al6(Si6O18)(BO3)3(OH)3O | Trig. 3m : R3m |
Oxy-uvite | CaMg3Al6(Si6O18)(BO3)3(OH)3O | |
Oxy-vanadium-dravite | NaV3(V4Mg2)(Si6O18)(BO3)3(OH)3O | Trig. 3m : R3m |
Povondraite | NaFe3+3(Mg2Fe3+4)(Si6O18)(BO3)3(OH)3O | Trig. 3m : R3m |
Princivalleite | Na(Mn2Al)Al6(Si6O18)(BO3)3(OH)3O | Trig. 3m : R3m |
Rossmanite | ◻(LiAl2)Al6(Si6O18)(BO3)3(OH)3(OH) | Trig. 3m : R3m |
Schorl | NaFe2+3Al6(Si6O18)(BO3)3(OH)3(OH) | Trig. 3m : R3m |
Tsilaisite | NaMn2+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 (Pb-analogue of Fluor-liddicoatite) | Pb(Li2Al)Al6(Si6O18)(BO3)3(OH)3F | |
Uvite | CaMg3(Al5Mg)(Si6O18)(BO3)3(OH)3(OH) | Trig. 3m : R3m |
Vanadio-oxy-chromium-dravite | NaV3(Cr4Mg2)(Si6O18)(BO3)3(OH)3O | Trig. 3m : R3m |
Vanadio-oxy-dravite | NaV3(Al4Mg2)(Si6O18)(BO3)3(OH)3O | Trig. 3m : R3m |
Common Associates
Related Minerals - Strunz-mindat Grouping
9.CK. | Fluor-schorl | NaFe2+3Al6(Si6O18)(BO3)3(OH)3F |
9.CK. | Darrellhenryite | Na(Al2Li)Al6(Si6O18)(BO3)3(OH)3O |
9.CK. | Adachiite | CaFe3Al6(Si5AlO18)(BO3)3(OH)3(OH) |
9.CK. | Bosiite | NaFe3+3(Al4Mg2)(Si6O18)(BO3)3(OH)3O |
9.CK. | Dutrowite | Na(Fe2+2.5Ti0.5)Al6(Si6O18)(BO3)3(OH)3O |
9.CK. | Celleriite | ◻(Mn2+2Al)Al6(Si6O18)(BO3)3(OH)3(OH) |
9.CK. | Princivalleite | Na(Mn2Al)Al6(Si6O18)(BO3)3(OH)3O |
9.CK. | Alumino-oxy-rossmanite | ◻Al3Al6(Si5AlO18)(BO3)3(OH)3O |
9.CK. | Ferro-bosiite | NaFe3+3(Al4Fe2+2)(Si6O18)(BO3)3(OH)3O |
9.CK. | Magnesio-dutrowite | Na(Mg2.5Ti0.5)Al6(Si6O18)(BO3)3(OH)3O |
9.CK.05 | Fluor-buergerite | NaFe3+3Al6(Si6O18)(BO3)3O3F |
9.CK.05 | Dravite | NaMg3Al6(Si6O18)(BO3)3(OH)3(OH) |
9.CK.05 | Elbaite | Na(Li1.5Al1.5)Al6(Si6O18)(BO3)3(OH)3(OH) |
9.CK.05 | Feruvite | CaFe2+3(Al5Mg)(Si6O18)(BO3)3(OH)3(OH) |
9.CK.05 | Foitite | ◻(Fe2+2Al)Al6(Si6O18)(BO3)3(OH)3(OH) |
9.CK.05 | Liddicoatite | Ca(Li2Al)Al6(Si6O18)(BO3)3(OH)3(OH) |
9.CK.05 | Olenite | NaAl3Al6(Si6O18)(BO3)3O3(OH) |
9.CK.05 | Povondraite | NaFe3+3(Mg2Fe3+4)(Si6O18)(BO3)3(OH)3O |
9.CK.05 | Schorl | NaFe2+3Al6(Si6O18)(BO3)3(OH)3(OH) |
9.CK.05 | Magnesio-foitite | ◻(Mg2Al)Al6(Si6O18)(BO3)3(OH)3(OH) |
9.CK.05 | Rossmanite | ◻(LiAl2)Al6(Si6O18)(BO3)3(OH)3(OH) |
9.CK.05 | Tsilaisite | NaMn2+3Al6(Si6O18)(BO3)3(OH)3(OH) |
9.CK.05 | Oxy-vanadium-dravite | NaV3(V4Mg2)(Si6O18)(BO3)3(OH)3O |
9.CK.05 | Oxy-dravite | Na(Al2Mg)(Al5Mg)(Si6O18)(BO3)3(OH)3O |
9.CK.05 | Oxy-rossmanite | ◻(Li0.5Al2.5)Al6(Si6O18)(BO3)3(OH)3O |
9.CK.05 | Luinaite-(OH) | NaFe2+3Al6(Si6O18)(BO3)3(OH)3(OH) |
9.CK.05 | Fluor-elbaite | Na(Li1.5Al1.5)Al6(Si6O18)(BO3)3(OH)3F |
9.CK.05 | Chromo-alumino-povondraite | NaCr3(Al4Mg2)(Si6O18)(BO3)3(OH)3O |
9.CK.05 | Fluor-dravite | NaMg3Al6(Si6O18)(BO3)3(OH)3F |
9.CK.05 | Oxy-schorl | Na(Fe2+2Al)Al6(Si6O18)(BO3)3(OH)3O |
9.CK.05 | Fluor-liddicoatite | Ca(Li2Al)Al6(Si6O18)(BO3)3(OH)3F |
9.CK.05 | Unnamed (F analogue of feruvite) | CaFe2+3(Al5Mg)(Si6O18)(BO3)3(OH)3F |
9.CK.05 | UM2000-64-SiO:BFeHKMg | (K,Na)Fe3+3(Mg2Fe3+4)Si6O18(BO3)3(OH)3O |
9.CK.05 | Oxy-chromium-dravite | NaCr3(Cr4Mg2)(Si6O18)(BO3)3(OH)3O |
9.CK.05 | Fluor-tsilaisite | NaMn2+3Al6(Si6O18)(BO3)3(OH)3F |
9.CK.05 | Vanadio-oxy-chromium-dravite | NaV3(Cr4Mg2)(Si6O18)(BO3)3(OH)3O |
9.CK.05 | Fluor-uvite | CaMg3(Al5Mg)(Si6O18)(BO3)3(OH)3F |
9.CK.05 | Vanadio-oxy-dravite | NaV3(Al4Mg2)(Si6O18)(BO3)3(OH)3O |
9.CK.05 | Maruyamaite | K(Al2Mg)(Al5Mg)(Si6O18)(BO3)3(OH)3O |
9.CK.05 | Lucchesiite | CaFe2+3 Al6(Si6O18)(BO3)3(OH)3O |
9.CK.05 | Oxy-foitite | ◻(Fe2+Al2)Al6(Si6O18)(BO3)3(OH)3O |
9.CK.05 | Oxy-uvite | CaMg3Al6(Si6O18)(BO3)3(OH)3O |
9.CK.05 | Magnesio-lucchesiite | CaMg3Al6(Si6O18)(BO3)3(OH)3O |
9.CK.05 | Uvite | CaMg3(Al5Mg)(Si6O18)(BO3)3(OH)3(OH) |
9.CK.05 | Fluor-rossmanite | ◻(Al2Li)Al6(Si6O18)(BO3)3(OH)3F |
9.CK.10 | Abenakiite-(Ce) | Na26Ce6(Si6O18)(PO4)6(CO3)6(SO2)O |
9.CK.15 | Scawtite | Ca7(Si3O9)2CO3 · 2H2O |
9.CK.20 | Steenstrupine-(Ce) | Na14Mn2+2Fe3+2Ce6Zr(Si6O18)2(PO4)6(PO3OH)(OH)2 · 2H2O |
9.CK.20 | Thorosteenstrupine | (Ca,Th,Mn)3Si4O11F · 6H2O |
Other Information
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-dravite
mindat.org URL:
https://www.mindat.org/min-1031.html
Please feel free to link to this page.
Please feel free to link to this page.
Search Engines:
References for Chromium-dravite
Reference List:
Dunn, Pete J. (1977) Chromium in dravite. Mineralogical Magazine, 41 (319) 408-410 doi:10.1180/minmag.1977.041.319.21
Bosi, Ferdinando, Lucchesi, Sergio, Reznitskii, Leonid (2004) Crystal chemistry of the dravite-chromdravite series. European Journal of Mineralogy, 16 (2) 345-352 doi:10.1127/0935-1221/2004/0016-0345
Localities for Chromium-dravite
Locality List
- 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.
All localities listed without proper references should be considered as questionable.
Brazil | |
| erroneously reported [MinRec 33:209] |
Canada | |
| Alexandre et al. (2014) |
Finland | |
| ... |
India | |
| - (see explanation under chromoaluminopovondraite) |
Pakistan | |
| - (2002) |
Russia | |
| Pekov (1998) |
| Jeff Weissman collection (purchased from Excalibur Mineral Company) |
| Pekov (1998) |
USA | |
| Marian Lupulescu (New York State Museum) |
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Srednyaya Padma mine, Zaonezhie peninsula, Medvezhyegorsky District, Republic of Karelia, Russia