Log In
Alluaudite
A valid IMA mineral species - grandfathered
This page is currently not sponsored. Click here to sponsor this page.
About Alluaudite
François Alluaud
Formula:
(Na,Ca)Mn2+(Fe3+,Mn2+,Fe2+,Mg)2(PO4)3
Colour:
Dirty yellow to brownish yellow, grayish green; surficially dull greenish black, brownish black, black, when altered
Hardness:
5½ - 6
Specific Gravity:
3.4 - 3.5
Crystal System:
Monoclinic
Member of:
Name:
Named by Alexis Damour in 1847 in honor of François Alluaud (II) [September 21, 1778-February 18, 1866], of Limoges, France, ceramicist and mineralogist who discovered the Chanteloube material. François Alluaud (I) was director of the Royal Limoges porcelain factory and founded his own porcelain factory in 1798 and died in 1799. His son, François Alluaud (II) was already a ceramicist, presumably working for his father and wrote mineralogical articles, etc. from 1808 through 1855 and received the Legion of Honor in 1858. François Alluaud (II) was mayor of Limoges 1830-1833. (Encyclopedia of Ceramics (1902) by William Percival Jervis.) François Alluaud named hureaulite (1825) and heterosite (1826).
Type Locality:
Alluaudite Group. Alluaudite-Ferroalluaudite Series.
The original alluaudite from the type locality did not contain appreciable ferrous iron and was originally defined more or less as it is in the present day, but for new knowledge about mineral structure, etc. In 1937, Percy Quensel unsuccessfully introduced mangan-alluaudite to supersede simple alluaudite and then used alluaudite to accommodate ferrous iron-bearing material. Quensel's usage was rejected in Dana's System of Mineralogy, 7th edition.
Occurs as an alteration product of Varulite and Arrojadite-(KFe).
The original alluaudite from the type locality did not contain appreciable ferrous iron and was originally defined more or less as it is in the present day, but for new knowledge about mineral structure, etc. In 1937, Percy Quensel unsuccessfully introduced mangan-alluaudite to supersede simple alluaudite and then used alluaudite to accommodate ferrous iron-bearing material. Quensel's usage was rejected in Dana's System of Mineralogy, 7th edition.
Occurs as an alteration product of Varulite and Arrojadite-(KFe).
Unique Identifiers
Mindat ID:
142
Long-form identifier:
mindat:1:1:142:1
Similar Names
| Alluadite (of Bernhardi) | A synonym of Dufrénite |
| Alluaudite (of Damour) | A synonym of Ferroalluaudite |
IMA Classification of Alluaudite
Approved, 'Grandfathered' (first described prior to 1959)
IMA Formula:
◻NaMn2+Fe3+2(PO4)3
Classification of Alluaudite
8.AC.10
8 : PHOSPHATES, ARSENATES, VANADATES
A : Phosphates, etc. without additional anions, without H2O
C : With medium-sized and large cations
8 : PHOSPHATES, ARSENATES, VANADATES
A : Phosphates, etc. without additional anions, without H2O
C : With medium-sized and large cations
Dana 7th ed.:
38.2.6.1
38.2.3.6
38 : ANHYDROUS NORMAL PHOSPHATES, ARSENATES, AND VANADATES
2 : (AB)5(XO4)3
38 : ANHYDROUS NORMAL PHOSPHATES, ARSENATES, AND VANADATES
2 : (AB)5(XO4)3
19.12.28
19 : Phosphates
12 : Phosphates of Mn
19 : Phosphates
12 : Phosphates of Mn
Mineral Symbols
As of 2021 there are now IMA–CNMNC approved mineral symbols (abbreviations) for each mineral species, useful for tables and diagrams.
Please only use the official IMA–CNMNC symbol. Older variants are listed for historical use only.
Please only use the official IMA–CNMNC symbol. Older variants are listed for historical use only.
| Symbol | Source | Reference for Standard |
|---|---|---|
| Ald | IMA–CNMNC | Warr, L.N. (2021). IMA–CNMNC approved mineral symbols. Mineralogical Magazine, 85(3), 291-320. doi:10.1180/mgm.2021.43 |
| Ald | The Canadian Mineralogist (2019) | The Canadian Mineralogist (2019) The Canadian Mineralogist list of symbols for rock- and ore-forming minerals (December 30, 2019). download |
Physical Properties of Alluaudite
Transparency:
Translucent
Colour:
Dirty yellow to brownish yellow, grayish green; surficially dull greenish black, brownish black, black, when altered
Comment:
yellow to yellow-green in transmitted light
Streak:
Brownish yellow
Hardness:
5½ - 6 on Mohs scale
Cleavage:
Distinct/Good
On {100} and {010} {110} , good.
On {100} and {010} {110} , good.
Density:
3.4 - 3.5 g/cm3 (Measured)
Optical Data of Alluaudite
Type:
Biaxial (+)
RI values:
nα = 1.782 nβ = 1.802 nγ = 1.835
2V:
Measured: 50° to 90°, Calculated: 78°
Max. Birefringence:
δ = 0.053
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 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:
r > v moderate
Pleochroism:
Weak
Comments:
X = pale olive-green, straw-yellow to greenish yellow; Z = pale olive-greenish to brownish yellow.
Chemistry of Alluaudite
Mindat Formula:
(Na,Ca)Mn2+(Fe3+,Mn2+,Fe2+,Mg)2(PO4)3
Element Weights:
Chemical Analysis
Oxide wt%:
| 1 | |
|---|---|
| P2O5 | 43,19 % |
| Al2O3 | 1,31 % |
| Fe2O3 | 6,42 % |
| FeO | 3,64 % |
| MnO | 17,23 % |
| MgO | 0,47 % |
| CaO | 1,31 % |
| Na2O | 4,94 % |
| Li2O | 0,04 % |
| H2O+ | 0,88 % |
| Insol | 0,81 % |
| Total: | 75 % |
Sample references:
| ID | Locality | Reference | Notes |
|---|---|---|---|
| 1 | Buranga pegmatite, Muhororo, Ngororero District, Western Province, Rwanda |
Crystallography of Alluaudite
Crystal System:
Monoclinic
Class (H-M):
2/m - Prismatic
Space Group:
B2/b
Setting:
C2/c
Cell Parameters:
a = 11.03 Å, b = 12.53 Å, c = 6.4 Å
β = 97.57°
β = 97.57°
Ratio:
a:b:c = 0.88 : 1 : 0.511
Unit Cell V:
876.81 ų (Calculated from Unit Cell)
Z:
4
Morphology:
Crystals platy to fibrous, to 1 cm; usually radiating fibrous, in nodular aggregates; granular, massive.
Twinning:
Twinning: Polysynthetic, with {101} as composition plane, seen in thin section.
Crystal Structure
Load
Unit Cell | Unit Cell Packed
2x2x2 | 3x3x3 | 4x4x4
Unit Cell | Unit Cell Packed
2x2x2 | 3x3x3 | 4x4x4
Show
Big Balls | Small Balls | Just Balls | Spacefill
Polyhedra Off | Si Polyhedra | All Polyhedra
Remove metal-metal sticks
Big Balls | Small Balls | Just Balls | Spacefill
Polyhedra Off | Si Polyhedra | All Polyhedra
Remove metal-metal sticks
Display Options
Black Background | White Background
Perspective On | Perspective Off
2D | Stereo | Red-Blue | Red-Cyan
Black Background | White Background
Perspective On | Perspective Off
2D | Stereo | Red-Blue | Red-Cyan
View
CIF File Best | x | y | z | a | b | c
CIF File Best | x | y | z | a | b | c
Rotation
Stop | Start
Stop | Start
Labels
Console Off | On | Grey | Yellow
Console Off | On | Grey | Yellow
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) |
|---|---|---|---|---|---|---|---|
| 0007139 | Alluaudite | Redhammer G J, Tippelt G, Bernroider M, Lottermoser W, Amthauer G, Roth G (2005) Hagendorfite (Na,Ca)MnFe2(PO4)3 from type locality Hagendorf (Bavaria, Germany): Crystal structure determination and 57Fe Mossbauer spectroscopy European Journal of Mineralogy 17 915-932 | 2005 | Buranga, Rwanda | 0 | 293 | |
| 0003758 | Alluaudite | Hatert F, Rebbouh L, Hermann R P, Fransolet A M, Long G J, Grandjean F (2005) Crystal chemistry of the hydrothermally synthesized Na2(Mn1-xFe2+x)2Fe3+(PO4)3 alluaudite-type solid solution American Mineralogist 90 653-662 |  | 2005 | 0 | 293 | |
| 0003757 | Alluaudite | Hatert F, Rebbouh L, Hermann R P, Fransolet A M, Long G J, Grandjean F (2005) Crystal chemistry of the hydrothermally synthesized Na2(Mn1-xFe2+x)2Fe3+(PO4)3 alluaudite-type solid solution American Mineralogist 90 653-662 | | 2005 | 0 | 293 | |
| 0003756 | Alluaudite | Hatert F, Rebbouh L, Hermann R P, Fransolet A M, Long G J, Grandjean F (2005) Crystal chemistry of the hydrothermally synthesized Na2(Mn1-xFe2+x)2Fe3+(PO4)3 alluaudite-type solid solution American Mineralogist 90 653-662 | | 2005 | 0 | 293 | |
| 0003755 | Alluaudite | Hatert F, Rebbouh L, Hermann R P, Fransolet A M, Long G J, Grandjean F (2005) Crystal chemistry of the hydrothermally synthesized Na2(Mn1-xFe2+x)2Fe3+(PO4)3 alluaudite-type solid solution American Mineralogist 90 653-662 | | 2005 | 0 | 293 | |
| 0003754 | Alluaudite | Hatert F, Rebbouh L, Hermann R P, Fransolet A M, Long G J, Grandjean F (2005) Crystal chemistry of the hydrothermally synthesized Na2(Mn1-xFe2+x)2Fe3+(PO4)3 alluaudite-type solid solution American Mineralogist 90 653-662 | | 2005 | 0 | 293 | |
| 0008874 | Alluaudite | Hatert F, Long G J, Hautot D, Fransolet A-M, Delwiche J, Hubin-Franskin M J, Grandjean F (2004) A structural, magnetic, and Mossbauer spectral study of several Na-Mn-Fe-bearing alluaudites Physics and Chemistry of Minerals 31 487-506 | 2004 | 0 | 293 | ||
| 0002974 | Alluaudite | Hatert F, Hermann R P, Long G J, Fransolet A M, Grandjean F (2003) An X-ray Rietveld, infrared, and Mossbauer spectral study of the NaMn(Fe1-xInx)2(PO4)3 alluaudite-type solid solution American Mineralogist 88 211-222 | | 2003 | 0 | 293 | |
| 0002973 | Alluaudite | Hatert F, Hermann R P, Long G J, Fransolet A M, Grandjean F (2003) An X-ray Rietveld, infrared, and Mossbauer spectral study of the NaMn(Fe1-xInx)2(PO4)3 alluaudite-type solid solution American Mineralogist 88 211-222 | | 2003 | 0 | 293 | |
| 0002972 | Alluaudite | Hatert F, Hermann R P, Long G J, Fransolet A M, Grandjean F (2003) An X-ray Rietveld, infrared, and Mossbauer spectral study of the NaMn(Fe1-xInx)2(PO4)3 alluaudite-type solid solution American Mineralogist 88 211-222 | | 2003 | 0 | 293 | |
| 0002971 | Alluaudite | Hatert F, Hermann R P, Long G J, Fransolet A M, Grandjean F (2003) An X-ray Rietveld, infrared, and Mossbauer spectral study of the NaMn(Fe1-xInx)2(PO4)3 alluaudite-type solid solution American Mineralogist 88 211-222 | | 2003 | 0 | 293 | |
| 0006583 | Alluaudite | Antenucci D, Fransolet A M, Miehe G, Tarte P (1995) Synthese et cristallochimie de NaCaCdMg2(PO4)3, Phosphate nouveau a structure alluaudite sans cation trivalent European Journal of Mineralogy 7 175-181 | 1995 | 0 | 293 | ||
| 0006478 | Alluaudite | Antenucci D, Miehe G, Tarte P, Schmahl W W, Fransolet A-M (1993) Combined X-ray Rietveld, infrared and Raman study of a new synthetic variety of alluaudite, NaCdIn2(PO4)3 European Journal of Mineralogy 5 207-213 | 1993 | 0 | 293 | ||
| 0000266 | Alluaudite | Moore P B (1971) Crystal chemistry of the alluaudite structure type: Contribution to the paragenesis of pegmatite phosphate giant crystals American Mineralogist 56 1955-1975 | | 1971 | 0 | 293 |
CIF Raw Data - click here to close
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 2.73 Å | (10) |
| 6.36 Å | (8) |
| 3.51 Å | (7) |
| 2.74 Å | (7) |
| 3.08 Å | (5) |
| 5.52 Å | (4) |
| 2.53 Å | (3) |
Geological Environment
Paragenetic Mode(s):
| Paragenetic Mode | Earliest Age (Ga) |
|---|---|
| Near-surface Processes | |
| 21 : Chemically precipitated carbonate, phosphate, iron formations | |
| High-? alteration and/or metamorphism | |
| 31 : Thermally altered carbonate, phosphate, and iron formations | |
| Stage 4b: Highly evolved igneous rocks | >3.0 |
| 34 : Complex granite pegmatites |
Geological Setting:
Very common in granite pegmatites, formed by sodium metasomatism of triphylite–lithiophilite, heterosite–purpurite, or ferrisicklerite; in phosphatic nodules in shales.
Type Occurrence of Alluaudite
General Appearance of Type Material:
Crystals platy to fibrous, to 1 cm; usually radiating fibrous, in nodular aggregates; granular, massive
Associated Minerals at Type Locality:
Boa Vista pegmatite, Barra do Cuieté, Conselheiro Pena, Minas Gerais, Brazil