Zaïrite
A valid IMA mineral species
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About Zaïrite
Flag of Zaïre
Formula:
BiFe3+3(PO4)2(OH)6
Colour:
Green, light olive green
Lustre:
Waxy, Dull
Hardness:
4½
Specific Gravity:
4.42 (Calculated)
Crystal System:
Trigonal
Member of:
Name:
Named by L. van Wambeke in 1975 after the country in which it was first discovered, Zaïre (now the Democratic Republic of the Congo).
Type Locality:
The ferric iron analogue of waylandite.
The phosphate analogue of Unnamed (As-analogue of Zaïrite).
The Bi (or Bi-PO3OH) analogue of UM2006-23-PO:AlBiCaFeH.
Medium to light olive-green irregular plates.
The phosphate analogue of Unnamed (As-analogue of Zaïrite).
The Bi (or Bi-PO3OH) analogue of UM2006-23-PO:AlBiCaFeH.
Medium to light olive-green irregular plates.
Name Encoding
ASCII-7:
Zairite
Unique Identifiers
Mindat ID:
4382
Long-form identifier:
mindat:1:1:4382:9
Similar Names
| Cerite | A synonym | |
| Cerite-(CeCa) | A valid IMA mineral species - grandfathered | (Ce7Ca2)◻Mg(SiO4)3(SiO3OH)4(OH)3 |
| Cerite-(La) | A synonym of Ferricerite-(LaCa) | |
| Sayrite | A valid IMA mineral species | Pb2(UO2)5O6(OH)2 · 4H2O |
| Surite | A valid IMA mineral species | (Pb,Ca)3(Al,Fe2+,Mg)2((Si,Al)4O10)(CO3)2(OH)2 |
| Ziroite | A valid IMA mineral species | ZrO2 |
| Zorite | A valid IMA mineral species | Na8(Ti,Nb)5(Si6O17)2(OH,O)5 · 14H2O |
IMA Classification of Zaïrite
Approved
IMA Formula:
Bi3+Fe3+3(PO4)2(OH)6
Approval year:
1975
First published:
1975
Classification of Zaïrite
8.BL.13
8 : PHOSPHATES, ARSENATES, VANADATES
B : Phosphates, etc., with additional anions, without H2O
L : With medium-sized and large cations, (OH, etc.):RO4 = 3:1
8 : PHOSPHATES, ARSENATES, VANADATES
B : Phosphates, etc., with additional anions, without H2O
L : With medium-sized and large cations, (OH, etc.):RO4 = 3:1
41.5.12.3
41 : ANHYDROUS PHOSPHATES, ETC.CONTAINING HYDROXYL OR HALOGEN
5 : (AB)2(XO4)Zq
41 : ANHYDROUS PHOSPHATES, ETC.CONTAINING HYDROXYL OR HALOGEN
5 : (AB)2(XO4)Zq
19.14.33
19 : Phosphates
14 : Phosphates of Fe and other metals
19 : Phosphates
14 : Phosphates of Fe and other metals
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 for Standard |
|---|---|---|
| Zaï | 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 Zaïrite
Waxy, Dull
Transparency:
Translucent
Colour:
Green, light olive green
Streak:
White
Hardness:
4½ on Mohs scale
Tenacity:
Brittle
Cleavage:
None Observed
Fracture:
Irregular/Uneven
Density:
4.42 g/cm3 (Calculated)
Optical Data of Zaïrite
Type:
Uniaxial (-)
RI values:
nω = 1.82 - 1.83 nε = 1.81
Birefringence:
Weak to moderate
Max. Birefringence:
δ = 0.010 - 0.020
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 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.
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:
Very 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.
Chemistry of Zaïrite
Mindat Formula:
BiFe3+3(PO4)2(OH)6
Element Weights:
Common Impurities:
Ca,Cu,Ba,S,Si,Te
Crystallography of Zaïrite
Crystal System:
Trigonal
Class (H-M):
3m(32/m) - Hexagonal Scalenohedral
Space Group:
R3m
Cell Parameters:
a = 7.015 Å, c = 16.365 Å
Ratio:
a:c = 1 : 2.333
Unit Cell V:
697.43 ų (Calculated from Unit Cell)
Z:
3
Morphology:
Found as irregular intersecting plates (<1 mm), perhaps fracture fillings with original mineral dissolved away.
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 5.71 Å | (100) |
| 4.87 Å | (10) |
| 3.50 Å | (40) |
| 2.95 Å | (90) |
| 2.85 Å | (10) |
| 2.73 Å | (20) |
| 2.16 Å | (10) |
| 1.877 Å | (10) |
Comments:
29-226
Geological Environment
Paragenetic Mode(s):
| Paragenetic Mode | Earliest Age (Ga) |
|---|---|
| Stage 7: Great Oxidation Event | <2.4 |
| 47a : [Near-surface hydration of prior minerals] | |
| 47c : [Carbonates, phosphates, borates, nitrates] |
Type Occurrence of Zaïrite
General Appearance of Type Material:
Medium to light olive green irregular plates.
Place of Conservation of Type Material:
Royal Museum of Central Africa, Tervuren, Belgium, RMG14065.
Geological Setting of Type Material:
Granite pegmatite.
Associated Minerals at Type Locality:
Synonyms of Zaïrite
Other Language Names for Zaïrite
Relationship of Zaïrite to other Species
Member of:
Other Members of Plumbogummite Group:
| Arsenobenauite | SrFe3+3(AsO4)(AsO3OH)(OH)6 | Trig. 3m(32/m) : R3m |
| Benauite | SrFe3+3(PO4)(PO3OH)(OH)6 | Trig. 3m(32/m) : R3m |
| Crandallite | CaAl3(PO4)(PO3OH)(OH)6 | Trig. 3m(32/m) : R3m |
| Eylettersite | Th0.75Al3(PO4)2(OH)6 | Trig. 3m(32/m) : R3m |
| Florencite-(Ce) | CeAl3(PO4)2(OH)6 | Trig. 3m(32/m) : R3m |
| Florencite-(La) | LaAl3(PO4)2(OH)6 | Trig. 3m(32/m) : R3m |
| Florencite-(Nd) | NdAl3(PO4)2(OH)6 | Trig. 3m(32/m) : R3m |
| Florencite-(Sm) | SmAl3(PO4)2(OH)6 | Trig. 3m(32/m) : R3m |
| Galloplumbogummite | Pb(Ga,Al,Ge)3(PO4)2(OH)6 | Trig. 3m : R3m |
| Gorceixite | BaAl3(PO4)(PO3OH)(OH)6 | Mon. m : Bm |
| Goyazite | SrAl3(PO4)(PO3OH)(OH)6 | Trig. 3m(32/m) : R3m |
| Kintoreite | PbFe3(PO4)(PO3OH)(OH)6 | Trig. 3m(32/m) : R3m |
| 'Kintoreite-2c' | PbFe3+3(PO4)2(OH,H2O)6 | |
| Plumbogummite | PbAl3(PO4)(PO3OH)(OH)6 | Trig. 3m(32/m) : R3m |
| Springcreekite | BaV3+3(PO4)2(OH,H2O)6 | Trig. 3m(32/m) : R3m |
| 'UM2006-23-PO:AlBiCaFeH' | (Ca,Bi)(Fe,Al)3(PO4)(PO3OH)(OH)6 | |
| 'Unnamed (As-analogue of Zaïrite)' | (Bi,Pb)Fe3+3(AsO4)2(OH)6 | |
| Waylandite | BiAl3(PO4)2(OH)6 | Trig. 3m(32/m) : R3m |
Common Associates
Associations Based on Photo Data:
| 3 photos of Zaïrite associated with Rooseveltite | Bi(AsO4) |
| 2 photos of Zaïrite associated with Ximengite | Bi(PO4) |
| 1 photo of Zaïrite associated with Bismoclite | BiOCl |
| 1 photo of Zaïrite associated with Phosphosiderite | FePO4 · 2H2O |
| 1 photo of Zaïrite associated with Quartz | SiO2 |
Related Minerals - Strunz-mindat Grouping
| 8.BL. | Kiryuite | NaMnAl(PO4)F3 |
| 8.BL. | Metaheimite | PbCu2(AsO4)(OH)3 |
| 8.BL. | Graulichite-(La) | LaFe3+3(AsO4)2(OH)6 |
| 8.BL. | Cloudite | BaFe3+3(PO4)(SO4)(OH)6 |
| 8.BL. | Oberwolfachite | SrFe3+3(AsO4)(SO4)(OH)6 |
| 8.BL. | Arsenobenauite | SrFe3+3(AsO4)(AsO3OH)(OH)6 |
| 8.BL.05 | Gallobeudantite | PbGa3(AsO4)(SO4)(OH)6 |
| 8.BL.05 | Slottaite | SrFe3+3(PO4)(SO4)(OH)6 |
| 8.BL.05 | Corkite | PbFe3+3(PO4)(SO4)(OH)6 |
| 8.BL.05 | Hidalgoite | PbAl3(AsO4)(SO4)(OH)6 |
| 8.BL.05 | Hinsdalite | PbAl3(PO4)(SO4)(OH)6 |
| 8.BL.05 | 'UM2011-07-POSO:AlBaH' | BaAl3(PO4)(SO4)(OH)6 |
| 8.BL.05 | Kemmlitzite | SrAl3(AsO4)(SO4)(OH)6 |
| 8.BL.05 | Beudantite | PbFe3+3(AsO4)(SO4)(OH)6 |
| 8.BL.05 | Weilerite | BaAl3(AsO4)(SO4)(OH)6 |
| 8.BL.05 | Woodhouseite | CaAl3(PO4)(SO4)(OH)6 |
| 8.BL.05 | Svanbergite | SrAl3(PO4)(SO4)(OH)6 |
| 8.BL.10 | Segnitite | PbFe3+3AsO4(AsO3OH)(OH)6 |
| 8.BL.10 | Arsenogoyazite | SrAl3(AsO4)(AsO3OH)(OH)6 |
| 8.BL.10 | Arsenogorceixite | BaAl3(AsO4)(AsO3OH)(OH)6 |
| 8.BL.10 | Dussertite | BaFe3+3(AsO4)(AsO3OH)(OH)6 |
| 8.BL.10 | Galloplumbogummite | Pb(Ga,Al,Ge)3(PO4)2(OH)6 |
| 8.BL.10 | Stibiosegnitite | Pb(Fe3+2.5Sb5+0.5)(AsO4)2(OH)6 |
| 8.BL.10 va | 'Viséite' | |
| 8.BL.10 | Arsenocrandallite | CaAl3(AsO4)(AsO3OH)(OH)6 |
| 8.BL.10 | Benauite | SrFe3+3(PO4)(PO3OH)(OH)6 |
| 8.BL.10 | Philipsbornite | PbAl3(AsO4)(AsO3OH)(OH)6 |
| 8.BL.10 | Crandallite | CaAl3(PO4)(PO3OH)(OH)6 |
| 8.BL.10 | Springcreekite | BaV3+3(PO4)2(OH,H2O)6 |
| 8.BL.10 | Eylettersite | Th0.75Al3(PO4)2(OH)6 |
| 8.BL.10 | Kintoreite | PbFe3(PO4)(PO3OH)(OH)6 |
| 8.BL.10 | Plumbogummite | PbAl3(PO4)(PO3OH)(OH)6 |
| 8.BL.10 | Gorceixite | BaAl3(PO4)(PO3OH)(OH)6 |
| 8.BL.10 | Goyazite | SrAl3(PO4)(PO3OH)(OH)6 |
| 8.BL.13 | Florencite-(Ce) | CeAl3(PO4)2(OH)6 |
| 8.BL.13 | Florencite-(La) | LaAl3(PO4)2(OH)6 |
| 8.BL.13 | Florencite-(Nd) | NdAl3(PO4)2(OH)6 |
| 8.BL.13 | Arsenoflorencite-(La) | LaAl3(AsO4)2(OH)6 |
| 8.BL.13 | 'Arsenoflorencite-(Nd)' | NdAl3(AsO4)2(OH)6 |
| 8.BL.13 | 'Unnamed (As-analogue of Zaïrite)' | (Bi,Pb)Fe3+3(AsO4)2(OH)6 |
| 8.BL.13 | Arsenoflorencite-(Ce) | CeAl3(AsO4)2(OH)6 |
| 8.BL.13 | Graulichite-(Ce) | CeFe3+3(AsO4)2(OH)6 |
| 8.BL.13 | 'Arsenowaylandite' | BiAl3(AsO4)2(OH)6 |
| 8.BL.13 | Waylandite | BiAl3(PO4)2(OH)6 |
| 8.BL.13 | Florencite-(Sm) | SmAl3(PO4)2(OH)6 |
| 8.BL.15 | Viitaniemiite | Na(Ca,Mn2+)Al(PO4)(F,OH)3 |
| 8.BL.25 | Pattersonite | PbFe3+3(PO4)2(OH)5 · H2O |
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 Zaïrite
mindat.org URL:
https://www.mindat.org/min-4382.html
Please feel free to link to this page.
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References for Zaïrite
Reference List:
Van Wambeke, L. (1975) La zaïrite, un nouveau minéral appartenant à la série de la crandallite. Bulletin de Minéralogie, 98 (6) 351-353 doi:10.3406/bulmi.1975.7016
Jambor, John L. (1999) Nomenclature of the alunite supergroup. The Canadian Mineralogist, 37 (6). 1323-1341
Localities for Zaïrite
Showing 7 localities.
symbol to view information about a locality.
The 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).
All localities listed without proper references should be considered as questionable.
Bolivia | |
| Joy Desor analyses by Raman and SEM-EDS. |
Canada | |
| Adex Mining |
DR Congo (TL) | |
| Van Wambeke (1975) |
Germany | |
| Dill et al. (2009) |
| Joy Désor Collection. Identified by ... |
Japan | |
| MORIMITSU et al. (2021) |
Portugal | |
| Alves (2016) |
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Sítio do Castelo Mine, Folgosinho, Gouveia, Guarda, Portugal