Burangaite
A valid IMA mineral species
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About Burangaite
Formula:
NaFe2+Al5(PO4)4(OH)6 · 2H2O
Na may be replaced by minor Ca.
Colour:
Blue; colorless
Hardness:
5
Crystal System:
Monoclinic
Member of:
Name:
Named for the type locality at the Buranga pegmatite, Gatumba District, Western Province, Rwanda.
Isostructural with:
Burangaite-Matioliite Series. Fe2+ analogue of Matioliite. A replacement product of scorzalite.
Several "Mg-rich" burangaites reported in the literature may, in fact, be matioliite (Atencio et al., 2006).
Several "Mg-rich" burangaites reported in the literature may, in fact, be matioliite (Atencio et al., 2006).
Unique Identifiers
Mindat ID:
802
Long-form identifier:
mindat:1:1:802:6
IMA Classification of Burangaite
Classification of Burangaite
8.DK.15
8 : PHOSPHATES, ARSENATES, VANADATES
D : Phosphates, etc. with additional anions, with H2O
K : With large and medium-sized cations, (OH, etc.):RO4 > 1:1 and < 2:1
8 : PHOSPHATES, ARSENATES, VANADATES
D : Phosphates, etc. with additional anions, with H2O
K : With large and medium-sized cations, (OH, etc.):RO4 > 1:1 and < 2:1
42.9.1.1
42 : HYDRATED PHOSPHATES, ETC.CONTAINING HYDROXYL OR HALOGEN
9 : (AB)7(XO4)4Zq·xH2O
42 : HYDRATED PHOSPHATES, ETC.CONTAINING HYDROXYL OR HALOGEN
9 : (AB)7(XO4)4Zq·xH2O
19.14.9
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 |
|---|---|---|
| Brg | 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 Burangaite
Colour:
Blue; colorless
Comment:
Crystals often show an hourglass structure with a blue core and colorless margin.
Streak:
Weakly bluish
Hardness:
5 on Mohs scale
Cleavage:
Perfect
Parallel to (100)
Parallel to (100)
Optical Data of Burangaite
Type:
Biaxial (-)
RI values:
nα = 1.611 nβ = 1.635 nγ = 1.643
2V:
Measured: 58° , Calculated: 58°
Max. Birefringence:
δ = 0.032
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:
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 biaxial acute bisectrix (Bxa) interference figure
- the conoscopic view for a grain cut perpendicular to the acute bisectrix, using
this mineral's 2V. The two small white dots mark the melatopes - the points
where the two optic axes emerge - and are shown only when they fall within the
field of view. The coloured bands are isochromatics, and the dark bands are
isogyres.
Rotate the stage: at 0°/90° the isogyres form a cross through the melatopes; at 45° they pull apart into curved hyperbolas. That splitting on rotation - absent in a uniaxial figure - is the standard diagnostic test for telling biaxial minerals from uniaxial ones. If 2V is large, the melatopes may fall outside the field of view, as they often do at the microscope too.
Rotate the stage: at 0°/90° the isogyres form a cross through the melatopes; at 45° they pull apart into curved hyperbolas. That splitting on rotation - absent in a uniaxial figure - is the standard diagnostic test for telling biaxial minerals from uniaxial ones. If 2V is large, the melatopes may fall outside the field of view, as they often do at the microscope too.
Dispersion:
relatively strong
Optical Extinction:
Z = b; X ∧ c = 11°.
Pleochroism:
Strong
Comments:
X = light blue; Y = dark blue; Z = colorless.
Comments:
Absorption: Y > X > Z.
Chemistry of Burangaite
Mindat Formula:
NaFe2+Al5(PO4)4(OH)6 · 2H2O
Na may be replaced by minor Ca.
Na may be replaced by minor Ca.
Element Weights:
Chemical Analysis
Oxide wt%:
| 1 | |
|---|---|
| P2O5 | 37.65 % |
| Al2O3 | 34.35 % |
| Fe2O3 | 1.14 % |
| FeO | 6.26 % |
| MgO | 2.00 % |
| MnO | 0.40 % |
| CaO | 1.88 % |
| Na2O | 2.93 % |
| H2O+ | 11.60 % |
| Insol | 2.06 % |
| Total: | 100.27 % |
Sample references:
Crystallography of Burangaite
Crystal System:
Monoclinic
Class (H-M):
2/m - Prismatic
Space Group:
B2/b
Setting:
C2/c
Cell Parameters:
a = 25.09 Å, b = 5.04 Å, c = 13.45 Å
β = 110.91°
β = 110.91°
Ratio:
a:b:c = 4.978 : 1 : 2.669
Unit Cell V:
1,588.79 ų (Calculated from Unit Cell)
Morphology:
Long prismatic crystals, characteristically bladed in appearance. Forms include {301}, {102}, {104}, , {223}, {311}, {223}, {311}, and {401}.
Crystal Structure
Load
Unit Cell | Unit Cell Packed
2x2x2 | 3x3x3 | 4x4x4
Unit Cell | Unit Cell Packed
2x2x2 | 3x3x3 | 4x4x4
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CIF File Best | x | y | z | a | b | c
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Data courtesy of the American Mineralogist Crystal Structure Database. Click on an AMCSD ID to view structure
| ID | Species | Reference | Link | Year | Locality | Pressure (GPa) | Temp (K) |
|---|---|---|---|---|---|---|---|
| 0005534 | Burangaite | Selway J B, Cooper M A, Hawthorne F C (1997) Refinement of the crystal structure of burangaite The Canadian Mineralogist 35 1515-1522 |  | 1997 | 0 | 293 |
CIF Raw Data - click here to close
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 11.71 Å | (100) |
| 3.081 Å | (90) |
| 3.115 Å | (70) |
| 4.86 Å | (41) |
| 3.318 Å | (39) |
| 2.044 Å | (32) |
| 1.6746 Å | (28) |
Geological Environment
Paragenetic Mode(s):
| Paragenetic Mode | Earliest Age (Ga) |
|---|---|
| Stage 4b: Highly evolved igneous rocks | >3.0 |
| 34 : Complex granite pegmatites | |
| Stage 7: Great Oxidation Event | <2.4 |
| 47a : [Near-surface hydration of prior minerals] | |
| 47c : [Carbonates, phosphates, borates, nitrates] |
Type Occurrence of Burangaite
General Appearance of Type Material:
Conspicuous bluish-green radiating crystals in aplite or as bluish, long prismatic crystals.
Place of Conservation of Type Material:
n.d.
Geological Setting of Type Material:
Granite pegmatite.
Associated Minerals at Type Locality:
Synonyms of Burangaite
Other Language Names for Burangaite
Relationship of Burangaite to other Species
Member of:
Other Members of Dufrénite Group:
| Bimbowrieite | NaMgFe3+5(PO4)4(OH)6 · 2H2O | Mon. 2/m : B2/b |
| Dufrénite | Ca0.5Fe2+Fe3+5(PO4)4(OH)6 · 2H2O | Mon. 2/m : B2/b |
| Gayite | NaMn2+Fe3+5(PO4)4(OH)6 · 2H2O | Mon. 2/m : B2/b |
| Matioliite | NaMgAl5(PO4)4(OH)6 · 2H2O | Mon. 2/m : B2/b |
| Natrodufrénite | NaFe3+Fe3+5(PO4)4O(OH)5(H2O)2 | Mon. 2/m : B2/b |
Forms a series with:
Common Associates
Associations Based on Photo Data:
| 5 photos of Burangaite associated with Berlinite | AlPO4 |
| 3 photos of Burangaite associated with Scorzalite | Fe2+Al2(PO4)2(OH)2 |
| 2 photos of Burangaite associated with Trolleite | Al4(PO4)3(OH)3 |
| 2 photos of Burangaite associated with Rutile | TiO2 |
| 2 photos of Burangaite associated with Augelite | Al2(PO4)(OH)3 |
| 1 photo of Burangaite associated with Wagnerite | Mg2(PO4)F |
| 1 photo of Burangaite associated with Amblygonite | LiAl(PO4)F |
Related Minerals - Strunz-mindat Grouping
| 8.DK. | Regerite | KFe6(PO4)4(OH)7(H2O)6 · 4H2O |
| 8.DK. | Richelsdorfite | Ca2Cu5Sb(AsO4)4(OH)6Cl · 6H2O |
| 8.DK. | Bimbowrieite | NaMgFe3+5(PO4)4(OH)6 · 2H2O |
| 8.DK. | Puttapaite | Pb2Mn2+2ZnCr3+4O2(AsO4)4(OH)6 · 12H2O |
| 8.DK.10 | Thalliumpharmacosiderite | TlFe3+4[(AsO4)3(OH)4] · 4H2O |
| 8.DK.10 | Natropharmacosiderite | NaFe3+4(AsO4)3(OH)4 · 4H2O |
| 8.DK.10 | Pharmacosiderite | KFe3+4(AsO4)3(OH)4 · 6-7H2O |
| 8.DK.10 | Plumbopharmacosiderite | Pb0.5Fe3+4(AsO4)3(OH)4 · 5H2O |
| 8.DK.10 | Strontiopharmacosiderite | Sr0.5Fe3+4[(AsO4)3(OH)4] · 4H2O |
| 8.DK.10 | Bariopharmacosiderite | Ba0.5Fe3+4(AsO4)3(OH)4 · 5H2O |
| 8.DK.10 | Hydroniumpharmacosiderite | (H3O)Fe3+4(AsO4)3(OH)4 · 4H2O |
| 8.DK.12 | Hydroniumpharmacoalumite | (H3O)Al4(AsO4)3(OH)4 · 4.5H2O |
| 8.DK.12 | Bariopharmacoalumite | Ba0.5Al4(AsO4)3(OH)4 · 4H2O |
| 8.DK.12 | Pharmacoalumite | KAl4(AsO4)3(OH)4 · 6.5H2O |
| 8.DK.12 | Calciopharmacoalumite | Ca0.5Al4(AsO4)3(OH)4 · 5H2O |
| 8.DK.12 | Natropharmacoalumite | NaAl4(AsO4)3(OH)4 · 4H2O |
| 8.DK.15 | Matioliite | NaMgAl5(PO4)4(OH)6 · 2H2O |
| 8.DK.15 | Natrodufrénite | NaFe3+Fe3+5(PO4)4O(OH)5(H2O)2 |
| 8.DK.15 | Dufrénite | Ca0.5Fe2+Fe3+5(PO4)4(OH)6 · 2H2O |
| 8.DK.15 | Gayite | NaMn2+Fe3+5(PO4)4(OH)6 · 2H2O |
| 8.DK.20 | Kidwellite | NaFe3+9+x(PO4)6(OH)11 · 3H2O, x = 0.33 |
| 8.DK.25 | Bleasdaleite | (Ca,Fe3+)2Cu5(Bi,Cu)(PO4)4(H2O,OH,Cl)13 |
| 8.DK.30 | Matulaite | (Fe3+,Al)Al7(PO4)4(PO3OH)2(OH)8(H2O)8 · 8H2O |
| 8.DK.35 | Krasnovite | Ba(Al,Mg)(PO4,CO3)(OH)2 · 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 Burangaite
mindat.org URL:
https://www.mindat.org/min-802.html
Please feel free to link to this page.
Please feel free to link to this page.
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References for Burangaite
Reference List:
von Knorring, O., Lehtinen, M., Sahama, Th.G. (1977) Burangaite, a new phosphate mineral from Rwanda. Bulletin of the Geological Society of Finland, 49 (1). 33-36 doi:10.17741/bgsf/49.1.006
Fleischer, Michael; Pabst, Adolf, White, John Sampson (1978) New mineral names. American Mineralogist, 63 (7-8). 793-796
Localities for Burangaite
Showing 6 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.
Austria | |
| Niedermayr et al. (2001) +1 other reference |
| Brandstätter et al. (2000) | |
Rwanda (TL) | |
| von Knorring et al. (1977) +2 other references |
Spain | |
| Vérez et al. (2024) |
Sweden | |
| Ek et al. (1990) +1 other reference |
USA | |
| Newmont Mining Corporation |
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Hålsjöberg, Torsby, Värmland County, Sweden