Althausite
A valid IMA mineral species
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About Althausite
Prof. Egon Althaus
Formula:
Mg4(PO4)2(OH,O)(F,◻)
Colour:
Pale gray, reddish brown; dark blue, green, black
Lustre:
Sub-Vitreous, Resinous
Hardness:
3½ - 4
Specific Gravity:
2.97
Crystal System:
Orthorhombic
Name:
Named in 1975 by Gunnar Raade and Magne Tysseland in honor of Prof. Egon Althaus (February 15, 1933-June 16, 2022), mineralogist at University of Karlsruhe, Germany.
Type Locality:
This rare magnesium phosphate was first described from serpentine-magnesite deposits in Modum, Buskerud, Norway. Later the mineral has also been found as a secondary product in granitic pegmatites, in Brazil. In pegmatites the colour of the mineral may vary from dark blue–green to black (Frost et al., 2014). It has also been been found in the Panasqueira Sn–W deposit.
Althausite may alter to apatite along the cleavage planes. This is especially typical for the althausite found at the type locality and Overntjern locality, Norway.
Althausite may alter to apatite along the cleavage planes. This is especially typical for the althausite found at the type locality and Overntjern locality, Norway.
Unique Identifiers
Mindat ID:
148
Long-form identifier:
mindat:1:1:148:5
IMA Classification of Althausite
Approved
Approval year:
1974
First published:
1975
Classification of Althausite
8.BB.25
8 : PHOSPHATES, ARSENATES, VANADATES
B : Phosphates, etc., with additional anions, without H2O
B : With only medium-sized cations, (OH, etc.):RO4 about 1:1
8 : PHOSPHATES, ARSENATES, VANADATES
B : Phosphates, etc., with additional anions, without H2O
B : With only medium-sized cations, (OH, etc.):RO4 about 1:1
41.6.5.1
41 : ANHYDROUS PHOSPHATES, ETC.CONTAINING HYDROXYL OR HALOGEN
6 : A2(XO4)Zq
41 : ANHYDROUS PHOSPHATES, ETC.CONTAINING HYDROXYL OR HALOGEN
6 : A2(XO4)Zq
19.3.16
19 : Phosphates
3 : Phosphates of Be and Mg
19 : Phosphates
3 : Phosphates of Be and Mg
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 |
|---|---|---|
| Ahs | 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 Althausite
Sub-Vitreous, Resinous
Transparency:
Translucent
Colour:
Pale gray, reddish brown; dark blue, green, black
Comment:
turning brown on alteration to apatite
Hardness:
3½ - 4 on Mohs scale
Tenacity:
Brittle
Cleavage:
Perfect
{010} perfect ; distinct along {110}
{010} perfect ; distinct along {110}
Density:
2.97 g/cm3 (Measured) 2.91 g/cm3 (Calculated)
Optical Data of Althausite
Type:
Biaxial (+)
RI values:
nα = 1.588 nβ = 1.592 nγ = 1.598
2V:
Measured: 70° , Calculated: 80°
Birefringence:
0.010
Max. Birefringence:
δ = 0.010
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:
Moderate (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:
Parallel
Pleochroism:
Non-pleochroic
Chemistry of Althausite
Mindat Formula:
Mg4(PO4)2(OH,O)(F,◻)
Element Weights:
Chemical Analysis
Oxide wt%:
| 1 | 2 | |
|---|---|---|
| Al2O3 | 0.53 % | |
| Fe2O3 | 1.37 % | |
| MnO | 0.07 % | |
| MgO | 45.38 % | 50.5 % |
| CaO | 4.50 % | |
| Na2O | 0.22 % | |
| P2O5 | 43.59 % | 44.4 % |
| SiO2 | 0.11 % | |
| F | 2.86 % | 3.04 % |
| Cl | 0.19 % | |
| H2O+ | 1.87 % | |
| H2O- | 0.07 % | |
| -O=F2 Cl2 | -1.24 % | |
| FeO | 0.80 % | |
| Total: | 99.52 % | 98.74 % |
Sample references:
| ID | Type | Locality | Reference | Notes |
|---|---|---|---|---|
| 1 | Type Specimen | Tingelstadtjern Quarry, Modum, Buskerud, Norway | Analyst: B. Bruun | |
| 2 | Overntjern Quarry, Overntjern, Modum, Buskerud, Norway | Microprobe analysis |
Crystallography of Althausite
Crystal System:
Orthorhombic
Class (H-M):
mmm(2/m2/m2/m) - Dipyramidal
Space Group:
Pnma
Setting:
Pnma
Cell Parameters:
a = 8.258(2) Å, b = 6.054(2) Å, c = 14.383(5) Å
Ratio:
a:b:c = 1.364 : 1 : 2.376
Unit Cell V:
719.06 ų (Calculated from Unit Cell)
Z:
8
Morphology:
Rare crude crystals are elongated along [001], flattened on {010}, showing {010}, {110}, {131}, to 3 cm; generally as cleavable masses.
Crystal Structure
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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) |
|---|---|---|---|---|---|---|---|
| 0000784 | Althausite | Romming C, Raade G (1980) The crystal structure of althausite, Mg4(PO4)2(OH,O)(F, ) American Mineralogist 65 488-498 |  | 1980 | 0 | 293 |
CIF Raw Data - click here to close
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 3.59 Å | (100) |
| 3.42 Å | (40) |
| 3.32 Å | (90) |
| 3.02 Å | (80) |
| 2.89 Å | (40) |
| 2.79 Å | (60) |
| 2.70 Å | (30) |
| 2.64 Å | (60) |
Comments:
29-869
Geological Environment
Paragenetic Mode(s):
| Paragenetic Mode | Earliest Age (Ga) |
|---|---|
| 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 | |
| Stage 5: Initiation of plate tectonics | <3.5-2.5 |
| 38 : Ophiolites |
Type Occurrence of Althausite
General Appearance of Type Material:
Cleavable masses and crude tabular crystals to 3 cm
Place of Conservation of Type Material:
Mineralogical-Geological Museum, Oslo University, Oslo, Norway, 21978, 22044, 22045.
Geological Setting of Type Material:
A serpentine-magnesite deposit
Associated Minerals at Type Locality:
Synonyms of Althausite
Other Language Names for Althausite
Dutch:Althausiet
French:Althausite
German:Althausit
Norwegian:Althausitt
Russian:Альтхаузит
Spanish:Althausita
Common Associates
Associations Based on Photo Data:
| 21 photos of Althausite associated with 'Apatite' | Ca5(PO4)3A |
| 15 photos of Althausite associated with Lizardite | Mg3(Si2O5)(OH)4 |
| 11 photos of Althausite associated with Holtedahlite | Mg2(PO4)(OH) |
| 11 photos of Althausite associated with Hematite | Fe2O3 |
| 8 photos of Althausite associated with 'Leuchtenbergite' | Mg5Al(AlSi3O10)(OH)8 |
| 7 photos of Althausite associated with Chlorapatite | Ca5(PO4)3Cl |
| 6 photos of Althausite associated with Heneuite | CaMg5(CO3)(PO4)3(OH) |
| 6 photos of Althausite associated with Raadeite | Mg7(PO4)2(OH)8 |
| 6 photos of Althausite associated with Serpentine Subgroup | D3[Si2O5](OH)4 |
| 6 photos of Althausite associated with Magnesite | MgCO3 |
Related Minerals - Strunz-mindat Grouping
| 8.BB. | Moabite | NiFe3+(PO4)O |
| 8.BB. | Tilasite | CaMg(AsO4)F |
| 8.BB. | Paulgrothite | Cu9Fe3+O4(PO4)4Cl3 |
| 8.BB. | Karlditmarite | Cu9O4(PO4)2(SO4)2 |
| 8.BB. | Milkovoite | Cu4O(PO4)(AsO4) |
| 8.BB.X | Arsenowagnerite | Mg2(AsO4)F |
| 8.BB.05 | Tavorite | LiFe3+(PO4)(OH) |
| 8.BB.05 | Amblygonite | LiAl(PO4)F |
| 8.BB.05 | Montebrasite | LiAl(PO4)(OH) |
| 8.BB.10 | Zwieselite | Fe2+2(PO4)F |
| 8.BB.10 | Triplite | Mn2+2(PO4)F |
| 8.BB.15 | 'Unnamed (Sb-analogue of Auriacusite)' | Fe3+Cu2+[(Sb,As)O4]O |
| 8.BB.15 | Joosteite | Mn2+(Mn3+,Fe3+)(PO4)O |
| 8.BB.15 | Hydroxylwagnerite | Mg2(PO4)(OH) |
| 8.BB.15 | Wagnerite | Mg2(PO4)F |
| 8.BB.15 | Stanĕkite | (Mn2+,Fe2+,Mg)Fe3+(PO4)O |
| 8.BB.15 | Triploidite | Mn2+2(PO4)(OH) |
| 8.BB.15 | Sarkinite | Mn2+2(AsO4)(OH) |
| 8.BB.15 | Wolfeite | Fe2+2(PO4)(OH) |
| 8.BB.20 | Holtedahlite | Mg2(PO4)(OH) |
| 8.BB.20 | Satterlyite | (Fe2+,Mg,Fe)12(PO4)5(PO3OH)(OH,O)6 |
| 8.BB.30 | Zincolivenite | CuZn(AsO4)(OH) |
| 8.BB.30 | Adamite | Zn2(AsO4)(OH) |
| 8.BB.30 | Libethenite | Cu2(PO4)(OH) |
| 8.BB.30 | Zincolibethenite | CuZn(PO4)(OH) |
| 8.BB.30 | Eveite | Mn2+2(AsO4)(OH) |
| 8.BB.30 | Olivenite | Cu2(AsO4)(OH) |
| 8.BB.30 | Auriacusite | Fe3+Cu2+(AsO4)O |
| 8.BB.35 | Paradamite | Zn2(AsO4)(OH) |
| 8.BB.35 | Tarbuttite | Zn2(PO4)(OH) |
| 8.BB.40 | Barbosalite | Fe2+Fe3+2(PO4)2(OH)2 |
| 8.BB.40 | Scorzalite | Fe2+Al2(PO4)2(OH)2 |
| 8.BB.40 | Lazulite | MgAl2(PO4)2(OH)2 |
| 8.BB.40 | Meizhouite | Fe2+V3+2(PO4)2(OH)2 |
| 8.BB.40 | Hentschelite | CuFe3+2(PO4)2(OH)2 |
| 8.BB.40 | Wilhelmkleinite | ZnFe3+2(AsO4)2(OH)2 |
| 8.BB.45 | Dokuchaevite | Cu8O2(VO4)3Cl3 |
| 8.BB.45 | Trolleite | Al4(PO4)3(OH)3 |
| 8.BB.45 | Yaroshevskite | Cu9O2(VO4)4Cl2 |
| 8.BB.50 | Namibite | Cu(BiO)2(VO4)(OH) |
| 8.BB.50 | Aleutite | [Cu5O2](AsO4)(VO4) · (Cu,K,Pb,Rb,Cs,)Cl |
| 8.BB.52a | Ericlaxmanite | Cu4O(AsO4)2 |
| 8.BB.52b | Kozyrevskite | Cu4O(AsO4)2 |
| 8.BB.55 | Phosphoellenbergerite | (Mg,◻)2Mg12(PO4,PO3OH)6(PO3OH,CO3)2(OH)6 |
| 8.BB.55 | Popovite | Cu5O2(AsO4)2 |
| 8.BB.60 | Urusovite | CuAl(AsO4)O |
| 8.BB.65 | Theoparacelsite | Cu3(As2O7)(OH)2 |
| 8.BB.70 | Turanite | Cu5(VO4)2(OH)4 |
| 8.BB.75 | Stoiberite | Cu5(VO4)2O2 |
| 8.BB.80 | Fingerite | Cu11(VO4)6O2 |
| 8.BB.85 | Averievite | Cu6(VO4)2O2Cl2 |
| 8.BB.90 | Richellite | CaFe3+2(PO4)2(OH,F)2 |
| 8.BB.90 | Lipscombite | Fe2+Fe3+2(PO4)2(OH)2 |
| 8.BB.90 | Zinclipscombite | ZnFe3+2(PO4)2(OH)2 |
Fluorescence of Althausite
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 Althausite
mindat.org URL:
https://www.mindat.org/min-148.html
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References for Althausite
Reference List:
Raade, Gunnar, Tysseland, Magne (1975) Althausite, a new mineral from Modum, Norway. Lithos, 8 (3) 215-219 doi:10.1016/0024-4937(75)90038-9
Fleischer, Michael, Cabri, Louis J. (1976) New Mineral names. American Mineralogist, 61 (5-6) 502-504
Rømming, Christian, Raade, Gunnar (1980) The crystal structure of althausite, Mg4(PO4)2(OH,O) (F,[]) American Mineralogist, 65 (5-6) 488-498
Frost, Ray L., López, Andrés, Xi, Yunfei, Scholz, Ricardo (2014) Vibrational spectroscopic characterization of the phosphate mineral althausite Mg2(PO4)(OH,F,O) – Implications for the molecular structure. Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, 120. 252-256 doi:10.1016/j.saa.2013.10.018
Localities for Althausite
Showing 9 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.
Brazil | |
| Frost et al. (2014) |
| Frost et al. (2014) |
Iran | |
| Jafari et al. (2019) |
Norway | |
| Raade et al. (1975) +1 other reference |
| Wilke (1976) |
| Raade et al. (1975) +1 other reference |
Portugal | |
| Fleischer et al. (1982) +1 other reference | |
USA | |
| Gnanou (2018) |
| Barrick Gold Corporation |
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Tingelstadtjern Quarry, Modum, Buskerud, Norway