Holtedahlite
A valid IMA mineral species
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About Holtedahlite
Olaf Holtedahl
Formula:
Mg2(PO4)(OH)
Colour:
Colorless
Lustre:
Vitreous
Hardness:
4½ - 5
Specific Gravity:
2.94
Crystal System:
Trigonal
Name:
First mentioned in Raade & Tysseland (1975) as "an unidentified Ca-Mg-phosphate". First described by Raade & Mladeck (1979).
Named in honor of Olaf Holtedahl (24 June 1885, Oslo, Norway - 28 August 1975), professor of geology at the University of Oslo. He was the recipient of the Wollastone Medal of the Geological Society of London and the Leopold von Buch Medal from Deutsche Geologische Gesellschaft.
Named in honor of Olaf Holtedahl (24 June 1885, Oslo, Norway - 28 August 1975), professor of geology at the University of Oslo. He was the recipient of the Wollastone Medal of the Geological Society of London and the Leopold von Buch Medal from Deutsche Geologische Gesellschaft.
Type Locality:
Unique Identifiers
Mindat ID:
1924
Long-form identifier:
mindat:1:1:1924:4
IMA Classification of Holtedahlite
Classification of Holtedahlite
8.BB.20
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
41.6.4.2
41 : ANHYDROUS PHOSPHATES, ETC.CONTAINING HYDROXYL OR HALOGEN
6 : A2(XO4)Zq
41 : ANHYDROUS PHOSPHATES, ETC.CONTAINING HYDROXYL OR HALOGEN
6 : A2(XO4)Zq
19.3.15
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 |
|---|---|---|
| Htd | 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 Holtedahlite
Vitreous
Transparency:
Transparent
Colour:
Colorless
Streak:
White
Hardness:
4½ - 5 on Mohs scale
Cleavage:
None Observed
Shows no cleavage
Shows no cleavage
Fracture:
Irregular/Uneven
Density:
2.94 g/cm3 (Measured) 2.936 g/cm3 (Calculated)
Optical Data of Holtedahlite
Type:
Uniaxial (-)
RI values:
nω = 1.599 nε = 1.597
Max. Birefringence:
δ = 0.002
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 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 Holtedahlite
Mindat Formula:
Mg2(PO4)(OH)
Element Weights:
Elements listed:
Crystallography of Holtedahlite
Crystal System:
Trigonal
Class (H-M):
3m - Ditrigonal Pyramidal
Space Group:
P31m
Cell Parameters:
a = 11.203(3) Å, c = 4.977(1) Å
Ratio:
a:c = 1 : 0.444
Unit Cell V:
540.96 ų (Calculated from Unit Cell)
Z:
6
Morphology:
Occurred as masses and irregular patches, no external form has been observed.
Comment:
Rømming & Raade (1989).
Crystal Structure
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Unit Cell | Unit Cell Packed
2x2x2 | 3x3x3 | 4x4x4
Unit Cell | Unit Cell Packed
2x2x2 | 3x3x3 | 4x4x4
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View
CIF File Best | x | y | z | a | b | c
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Rotation
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Labels
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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) |
|---|---|---|---|---|---|---|---|
| 0014622 | Holtedahlite | Romming C, Raade G (1989) The crystal structure of natural and synthetic holtedahlite Mineralogy and Petrology 40 91-100 | 1989 | synthetic | 0 | 293 | |
| 0014621 | Holtedahlite | Romming C, Raade G (1989) The crystal structure of natural and synthetic holtedahlite Mineralogy and Petrology 40 91-100 | 1989 | Tingelstadtjern serpentine-magnesium deposit, Modum, Norway | 0 | 293 |
CIF Raw Data - click here to close
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 3.722 Å | (90) |
| 3.475 Å | (50) |
| 3.234 Å | (30) |
| 2.796 Å | (30) |
| 2.438 Å | (100) |
| 2.177 Å | (30) |
| 1.859 Å | (30) |
Geological Environment
Paragenetic Mode(s):
| Paragenetic Mode | Earliest Age (Ga) |
|---|---|
| Stage 3b: Earth’s earliest hydrosphere | >4.45 |
| 13 : Hadean serpentinization | |
| Stage 4b: Highly evolved igneous rocks | >3.0 |
| 35 : Ultra-alkali and agpaitic igneous rocks | |
| Stage 7: Great Oxidation Event | <2.4 |
| 45b : [Other oxidized fumarolic minerals] |
Type Occurrence of Holtedahlite
General Appearance of Type Material:
Colorless masses and patches intimately associated with althausite and apatite.
Place of Conservation of Type Material:
The Natural History Museum in Oslo
Geological Setting of Type Material:
Serpentinite-magnesite deposit.
Associated Minerals at Type Locality:
Synonyms of Holtedahlite
Other Language Names for Holtedahlite
Common Associates
Associations Based on Photo Data:
| 11 photos of Holtedahlite associated with Althausite | Mg4(PO4)2(OH,O)(F,◻) |
| 6 photos of Holtedahlite associated with Lizardite | Mg3(Si2O5)(OH)4 |
| 5 photos of Holtedahlite associated with 'Apatite' | Ca5(PO4)3A |
| 3 photos of Holtedahlite associated with Chlorapatite | Ca5(PO4)3Cl |
| 1 photo of Holtedahlite associated with Hydroxylapatite | Ca5(PO4)3(OH) |
| 1 photo of Holtedahlite associated with Phosphoellenbergerite | (Mg,◻)2Mg12(PO4,PO3OH)6(PO3OH,CO3)2(OH)6 |
| 1 photo of Holtedahlite associated with Heneuite | CaMg5(CO3)(PO4)3(OH) |
| 1 photo of Holtedahlite associated with Raadeite | Mg7(PO4)2(OH)8 |
| 1 photo of Holtedahlite associated with Hematite | Fe2O3 |
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 | Satterlyite | (Fe2+,Mg,Fe)12(PO4)5(PO3OH)(OH,O)6 |
| 8.BB.25 | Althausite | Mg4(PO4)2(OH,O)(F,◻) |
| 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 |
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 Holtedahlite
mindat.org URL:
https://www.mindat.org/min-1924.html
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Please feel free to link to this page.
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References for Holtedahlite
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
Raade, Gunnar, Mladeck, Micael H (1979) Holtedahlite, a new magnesium phosphate from Modum, Norway. Lithos, 12 (4) 283-287 doi:10.1016/0024-4937(79)90019-7
Fleischer, Michael, Cabri, Louis J., Chao, G. Y., Pabst, Adolf (1980) New Mineral Names. American Mineralogist, 65 (7-8) 808-814
Localities for Holtedahlite
Showing 1 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.
Norway (TL) | |
| Raade et al. (1979) |
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Tingelstadtjern Quarry, Modum, Buskerud, Norway