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Oxy-foitite

A valid IMA mineral species
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Formula:
◻(Fe2+Al2)Al6(Si6O18)(BO3)3(OH)3O
Colour:
Black
Lustre:
Vitreous
Hardness:
7
Specific Gravity:
3.143 (Calculated)
Crystal System:
Trigonal
Name:
Named according to the IMA nomenclature for tourmaline group minerals, its relationship to foitite, and the dominance of oxygen over hydroxyl.
The FeAl2-O-analogue of foitite. Oxy-foitite belongs to the X-site vacant group of the tourmaline supergroup minerals, and shows chemical relationships with foitite through the substitution Y Al3+ + WO2 → YFe2+ + W(OH)1–.


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Unique IdentifiersHide

Mindat ID:
50777
Long-form identifier:
mindat:1:1:50777:6

IMA Classification of Oxy-foititeHide

Classification of Oxy-foititeHide

9.CK.05

9 : SILICATES (Germanates)
C : Cyclosilicates
K : [Si6O18]12- 6-membered single rings, with insular complex anions

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

Physical Properties of Oxy-foititeHide

Vitreous
Colour:
Black
Streak:
Grey
Hardness:
Comment:
~7
Fracture:
Sub-Conchoidal
Density:
3.143 g/cm3 (Calculated)

Optical Data of Oxy-foititeHide

Type:
Uniaxial (-)
RI values:
nω = 1.660(5) nε = 1.630(5)
Max. Birefringence:
δ = 0.030
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 ”m 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:
High (positive)
Relative to Canada balsam mounting medium (n ≈ 1.537).

This shows the grain boundary and Becke line effect under plane-polarised light, based on the contrast between this mineral's average refractive index and the mounting medium. It does not take into account mineral colouration.
In focus
Interference Figure:
This shows the idealized uniaxial interference figure - the conoscopic (convergent-light, Bertrand-lens-in) view, for a grain cut with the optic axis centred and vertical. The coloured rings are isochromatics, computed with the same physics as the Michel-Lévy bar above; the dark cross is the isogyre.

For a genuinely uniaxial mineral viewed this way, that cross stays perfectly stationary if you rotate the stage - unlike a biaxial mineral, where it splits apart on rotation. That invariance is itself the standard diagnostic test for telling uniaxial and biaxial minerals apart at the microscope.
Pleochroism:
Visible
Comments:
In plane-polarized light: O = dark brown and E = pale brown

Chemistry of Oxy-foititeHide

Mindat Formula:
◻(Fe2+Al2)Al6(Si6O18)(BO3)3(OH)3O
Element Weights:
Element% weight
O51.045 %
Al22.215 %
Si17.343 %
Fe5.747 %
B3.338 %
H0.311 %

Calculated from ideal end-member formula.
O
Al
Si
Fe
B
H

Crystallography of Oxy-foititeHide

Crystal System:
Trigonal
Class (H-M):
3m(32/m) - Hexagonal Scalenohedral
Space Group:
R3m
Cell Parameters:
a = 15.9387(3) Å, c = 7.1507(1) Å
Ratio:
a:c = 1 : 0.449
Unit Cell V:
1573.2 ų
Z:
3

X-Ray Powder DiffractionHide

Geological EnvironmentHide

Paragenetic Mode(s):
Paragenetic ModeEarliest Age (Ga)
Stage 4a: Earth’s earliest continental crust>4.4-3.0
19 : Granitic intrusive rocks
Near-surface Processes
23 : Subaerial aqueous alteration by non-redox-sensitive fluids (see also #47)
26 : Hadean detrital minerals
Stage 4b: Highly evolved igneous rocks>3.0
34 : Complex granite pegmatites
Stage 5: Initiation of plate tectonics<3.5-2.5
40 : Regional metamorphism (greenschist, amphibolite, granulite facies)

Type Occurrence of Oxy-foititeHide

General Appearance of Type Material:
Crystals up to ~1 cm in size, subhedral, prismatic, and striated parallel to [0001].
Place of Conservation of Type Material:
Mineralogical collections of the Museum of Earth Sciences, Department of Earth Sciences, Sapienza University, P.le A. Moro 5, 00185 Roma, Italy (catalogue number 8829/84).
Geological Setting of Type Material:
High-grade migmatitic gneisses of pelitic composition.
Associated Minerals at Type Locality:

Synonyms of Oxy-foititeHide

Other Language Names for Oxy-foititeHide

Relationship of Oxy-foitite 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
Chromium-draviteNaMg3Cr3+6(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-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

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.05Chromium-draviteNaMg3Cr3+6(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.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 : B2/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

Fluorescence of Oxy-foititeHide

Not fluorescent

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 Oxy-foititeHide

References for Oxy-foititeHide

Localities for Oxy-foititeHide

Showing 4 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.
Australia (TL)
 
  • New South Wales
    • Beresford Co.
      • Snowy Mountains district
HÄlenius et al. (2016) +2 other references
China
 
  • Sichuan
    • GarzĂȘ Autonomous Prefecture (Ganzi Autonomous Prefecture)
      • Yajiang County
        • Kangding pegmatite field
Qin et al. (2023)
Russia
 
  • Chukotka Autonomous Okrug
    • Chukchi Peninsula (Chukotka Peninsula; Chukotski Peninsula)
Baksheev et al. (2025)
  • Tuva
    • Pi-Khem District
Baksheev et al. (2025)
 
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