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Oxy-foitite
A valid IMA mineral species
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Formula:
â»(Fe2+Al2)Al6(Si6O18)(BO3)3(OH)3O
Colour:
Black
Lustre:
Vitreous
Hardness:
7
Specific Gravity:
3.143 (Calculated)
Crystal System:
Trigonal
Member of:
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 â YFe2+ + W(OH)1â.
Unique Identifiers
Mindat ID:
50777
Long-form identifier:
mindat:1:1:50777:6
IMA Classification of Oxy-foitite
Approved
Approval year:
2016
First published:
2017
Classification of Oxy-foitite
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
Mineral Symbols
As of 2021 there are now IMAâCNMNC approved mineral symbols (abbreviations) for each mineral species, useful for tables and diagrams.
| Symbol | Source | Reference for Standard |
|---|---|---|
| Ofoi | IMAâCNMNC | Warr, L.N. (2021). IMAâCNMNC approved mineral symbols. Mineralogical Magazine, 85(3), 291-320. doi:10.1180/mgm.2021.43 |
Physical Properties of Oxy-foitite
Vitreous
Colour:
Black
Streak:
Grey
Hardness:
7 on Mohs scale
Comment:
~7
Fracture:
Sub-Conchoidal
Density:
3.143 g/cm3 (Calculated)
Optical Data of Oxy-foitite
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.
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.
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).
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.
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-foitite
Mindat Formula:
â»(Fe2+Al2)Al6(Si6O18)(BO3)3(OH)3O
Element Weights:
Crystallography of Oxy-foitite
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 Ă
Âł
Z:
3
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 6.357 Ă | (51) |
| 4.220 Ă | (47) |
| 3.990 Ă | (49) |
| 3.466 Ă | (100) |
| 2.953 Ă | (87) |
| 2.579 Ă | (98) |
| 2.048 Ă | (30) |
| 2.041 Ă | (50) |
Locality:
Geological Environment
Paragenetic Mode(s):
| Paragenetic Mode | Earliest Age (Ga) |
|---|---|
| Stage 4a: Earthâs 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-foitite
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-foitite
Other Language Names for Oxy-foitite
Dutch:Oxy-foitiet
German:Oxy-Foitit
Relationship of Oxy-foitite to other Species
Member of:
Other Members of Tourmaline:
| Adachiite | CaFe3Al6(Si5AlO18)(BO3)3(OH)3(OH) | Trig. 3m : R3m |
| Alumino-oxy-rossmanite | â»Al3Al6(Si5AlO18)(BO3)3(OH)3O | Trig. 3m : R3m |
| Bosiite | NaFe3+3(Al4Mg2)(Si6O18)(BO3)3(OH)3O | Trig. 3m : R3m |
| Celleriite | â»(Mn2+2Al)Al6(Si6O18)(BO3)3(OH)3(OH) | Trig. 3m : R3m |
| Chromium-dravite | NaMg3Cr3+6(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 |
| Ertlite | NaAl3Al6(Si4B2O18)(BO3)3(OH)3O | 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 | â»(Al2Li)Al6(Si6O18)(BO3)3(OH)3F | Trig. 3m(32/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 | â»(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 | â»(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-schorl | Na(Fe2+2Al)Al6(Si6O18)(BO3)3(OH)3O | Trig. 3m : R3m |
| 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 | â»(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,â»)(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)' | â»(Mn2+2Al)Al6(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 |
Related Minerals - Strunz-mindat Grouping
| 9.CK. | Adachiite | CaFe3Al6(Si5AlO18)(BO3)3(OH)3(OH) |
| 9.CK. | Magnesio-dutrowite | Na(Mg2.5Ti0.5)Al6(Si6O18)(BO3)3(OH)3O |
| 9.CK. | Darrellhenryite | Na(Al2Li)Al6(Si6O18)(BO3)3(OH)3O |
| 9.CK. | Fluor-schorl | NaFe2+3Al6(Si6O18)(BO3)3(OH)3F |
| 9.CK. | Princivalleite | Na(Mn2Al)Al6(Si6O18)(BO3)3(OH)3O |
| 9.CK. | Alumino-oxy-rossmanite | â»Al3Al6(Si5AlO18)(BO3)3(OH)3O |
| 9.CK. | Dutrowite | Na(Fe2+2.5Ti0.5)Al6(Si6O18)(BO3)3(OH)3O |
| 9.CK. | Ferro-bosiite | NaFe3+3(Al4Fe2+2)(Si6O18)(BO3)3(OH)3O |
| 9.CK. | Bosiite | NaFe3+3(Al4Mg2)(Si6O18)(BO3)3(OH)3O |
| 9.CK. | Celleriite | â»(Mn2+2Al)Al6(Si6O18)(BO3)3(OH)3(OH) |
| 9.CK.05 | Feruvite | CaFe2+3(Al5Mg)(Si6O18)(BO3)3(OH)3(OH) |
| 9.CK.05 | Chromium-dravite | NaMg3Cr3+6(Si6O18)(BO3)3(OH)3(OH) |
| 9.CK.05 | Fluor-rossmanite | â»(Al2Li)Al6(Si6O18)(BO3)3(OH)3F |
| 9.CK.05 | Oxy-schorl | Na(Fe2+2Al)Al6(Si6O18)(BO3)3(OH)3O |
| 9.CK.05 | Fluor-elbaite | Na(Li1.5Al1.5)Al6(Si6O18)(BO3)3(OH)3F |
| 9.CK.05 | Dravite | NaMg3Al6(Si6O18)(BO3)3(OH)3(OH) |
| 9.CK.05 | Fluor-uvite | CaMg3(Al5Mg)(Si6O18)(BO3)3(OH)3F |
| 9.CK.05 | Foitite | â»(Fe2+2Al)Al6(Si6O18)(BO3)3(OH)3(OH) |
| 9.CK.05 | Vanadio-oxy-dravite | NaV3(Al4Mg2)(Si6O18)(BO3)3(OH)3O |
| 9.CK.05 | Fluor-buergerite | NaFe3+3Al6(Si6O18)(BO3)3O3F |
| 9.CK.05 | 'Unnamed (F analogue of feruvite)' | CaFe2+3(Al5Mg)(Si6O18)(BO3)3(OH)3F |
| 9.CK.05 | Ertlite | NaAl3Al6(Si4B2O18)(BO3)3(OH)3O |
| 9.CK.05 | Tsilaisite | NaMn2+3Al6(Si6O18)(BO3)3(OH)3(OH) |
| 9.CK.05 | Fluor-liddicoatite | Ca(Li2Al)Al6(Si6O18)(BO3)3(OH)3F |
| 9.CK.05 | Uvite | CaMg3(Al5Mg)(Si6O18)(BO3)3(OH)3(OH) |
| 9.CK.05 | Elbaite | Na(Li1.5Al1.5)Al6(Si6O18)(BO3)3(OH)3(OH) |
| 9.CK.05 | Fluor-tsilaisite | NaMn2+3Al6(Si6O18)(BO3)3(OH)3F |
| 9.CK.05 | Liddicoatite | Ca(Li2Al)Al6(Si6O18)(BO3)3(OH)3(OH) |
| 9.CK.05 | Vanadio-oxy-chromium-dravite | NaV3(Cr4Mg2)(Si6O18)(BO3)3(OH)3O |
| 9.CK.05 | Rossmanite | â»(LiAl2)Al6(Si6O18)(BO3)3(OH)3(OH) |
| 9.CK.05 | Oxy-vanadium-dravite | NaV3(V4Mg2)(Si6O18)(BO3)3(OH)3O |
| 9.CK.05 | Olenite | NaAl3Al6(Si6O18)(BO3)3O3(OH) |
| 9.CK.05 | 'UM2000-64-SiO:BFeHKMg' | (K,Na)Fe3+3(Mg2Fe3+4)Si6O18(BO3)3(OH)3O |
| 9.CK.05 | Magnesio-lucchesiite | CaMg3Al6(Si6O18)(BO3)3(OH)3O |
| 9.CK.05 | Povondraite | NaFe3+3(Mg2Fe3+4)(Si6O18)(BO3)3(OH)3O |
| 9.CK.05 | Lucchesiite | CaFe2+3 Al6(Si6O18)(BO3)3(OH)3O |
| 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-dravite | Na(Al2Mg)(Al5Mg)(Si6O18)(BO3)3(OH)3O |
| 9.CK.05 | Oxy-chromium-dravite | NaCr3(Cr4Mg2)(Si6O18)(BO3)3(OH)3O |
| 9.CK.05 | 'Luinaite-(OH)' | NaFe2+3Al6(Si6O18)(BO3)3(OH)3(OH) |
| 9.CK.05 | Schorl | NaFe2+3Al6(Si6O18)(BO3)3(OH)3(OH) |
| 9.CK.05 | Magnesio-foitite | â»(Mg2Al)Al6(Si6O18)(BO3)3(OH)3(OH) |
| 9.CK.05 | Maruyamaite | K(Al2Mg)(Al5Mg)(Si6O18)(BO3)3(OH)3O |
| 9.CK.10 | Abenakiite-(Ce) | Na26Ce6(Si6O18)(PO4)6(CO3)6(SO2)O |
| 9.CK.15 | Scawtite | Ca7(Si3O9)2CO3 · 2H2O |
| 9.CK.20 | Thorosteenstrupine | (Ca,Th,Mn)3Si4O11F · 6H2O |
| 9.CK.20 | Steenstrupine-(Ce) | Na14Mn2+2Fe3+2Ce6Zr(Si6O18)2(PO4)6(PO3OH)(OH)2 · 2H2O |
Fluorescence of Oxy-foitite
Not fluorescent
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 Oxy-foitite
mindat.org URL:
https://www.mindat.org/min-50777.html
Please feel free to link to this page.
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References for Oxy-foitite
Reference List:
HÄlenius, U., Hatert, F., Pasero, M., Mills, S. J. (2016) New minerals and nomenclature modifications approved in 2016, CNMNC Newsletter No 34. Mineralogical Magazine, 80 (7) 1315-1321 doi:10.1180/minmag.2016.080.086
Localities for Oxy-foitite
Showing 4 localities.
Locality List
- This locality has map coordinates listed.
- This locality has estimated coordinates.
â - 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).
All localities listed without proper references should be considered as questionable.
Australia (TL) | |
| HÄlenius et al. (2016) +2 other references |
China | |
| Qin et al. (2023) |
Russia | |
| Baksheev et al. (2025) |
| Baksheev et al. (2025) |
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