Holtedahlite
This page is currently not sponsored. Click here to sponsor this page.
About Holtedahlite
Formula:
Mg2(PO4)(OH)
Colour:
Colorless
Lustre:
Vitreous
Hardness:
4½ - 5
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:
Classification of Holtedahlite
Approved
First Published:
1979
7/B.04-20
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
Physical Properties of Holtedahlite
Vitreous
Transparency:
Transparent
Colour:
Colorless
Hardness:
4½ - 5 on Mohs scale
Cleavage:
None Observed
Shows no cleavage
Shows no cleavage
Fracture:
Irregular/Uneven
Optical Data of Holtedahlite
Type:
Uniaxial (-)
RI values:
nω = 1.599 nε = 1.597
Max Birefringence:
δ = 0.002

Image shows birefringence interference colour range (at 30µm thickness)
and does not take into account mineral colouration.
and does not take into account mineral colouration.
Surface Relief:
Moderate
Chemical Properties of Holtedahlite
Formula:
Mg2(PO4)(OH)
IMA Formula:
Mg12(PO3OH,CO3)(PO4)5(OH,O)6
Crystallography of Holtedahlite
Crystal System:
Trigonal
Class (H-M):
3m - Ditrigonal Pyramidal
Space Group:
P3 1m
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)
Morphology:
Occured as masses and irregular patches, no external form has been observed
Comment:
Rømming & Raade (1989),
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 depoposite
Associated Minerals at Type Locality:
Synonyms of Holtedahlite
Other Language Names for Holtedahlite
Common Associates
Althausite | Mg4(PO4)2(OH,O)(F,☐) |
Apatite | "Apatite" is a field term for unidentified calcium phosphate members of the apatite group. |
Associated Minerals Based on Photo Data:
Althausite | 2 photos of Holtedahlite associated with Althausite on mindat.org. |
Hematite | 1 photo of Holtedahlite associated with Hematite on mindat.org. |
Chlorapatite | 1 photo of Holtedahlite associated with Chlorapatite on mindat.org. |
Lizardite | 1 photo of Holtedahlite associated with Lizardite on mindat.org. |
Apatite | 1 photo of Holtedahlite associated with Apatite on mindat.org. |
Related Minerals - Nickel-Strunz Grouping
8.BB.X | Arsenowagnerite | Mg2(AsO4)F | Mon. 2/m : P21/b |
8.BB.05 | Amblygonite | LiAl(PO4)F | Tric. 1 : P1 |
8.BB.05 | Montebrasite | LiAl(PO4)(OH) | Tric. 1 : P1 |
8.BB.05 | Tavorite | LiFe3+(PO4)(OH) | Tric. 1 : P1 |
8.BB.10 | Triplite | (Mn2+,Fe2+)2(PO4)(F,OH) | Mon. 2/m |
8.BB.10 | Zwieselite | (Fe2+,Mn2+)2(PO4)F | Mon. 2/m : P21/b |
8.BB.15 | Sarkinite | Mn2+2(AsO4)(OH) | Mon. 2/m : P2/m |
8.BB.15 | Triploidite | (Mn2+,Fe2+)2(PO4)(OH) | Mon. 2/m : P2/b |
8.BB.15 | Wagnerite | (Mg,Fe2+)2(PO4)F | Mon. 2/m : P21/b |
8.BB.15 | Wolfeite | (Fe2+,Mn2+)2(PO4)(OH) | Mon. 2/m : P21/b |
8.BB.15 | Stanĕkite | (Mn2+,Fe2+,Mg)Fe3+(PO4)O | Mon. |
8.BB.15 | Joosteite | Mn2+(Mn3+,Fe3+)(PO4)O | Mon. 2/m |
8.BB.15 | Hydroxylwagnerite | Mg2(PO4)(OH) | Mon. 2/m : P21/b |
8.BB.20 | Satterlyite | (Fe2+,Mg,Fe)12(PO4)5(PO3OH)(OH,O)6 | Trig. 3m (3 2/m) : P3 1m |
8.BB.25 | Althausite | Mg4(PO4)2(OH,O)(F,☐) | Orth. mmm (2/m 2/m 2/m) : Pnma |
8.BB.30 | Adamite | Zn2(AsO4)(OH) | Orth. mmm (2/m 2/m 2/m) : Pnnm |
8.BB.30 | Eveite | Mn2+2(AsO4)(OH) | Orth. mmm (2/m 2/m 2/m) : Pnnm |
8.BB.30 | Libethenite | Cu2(PO4)(OH) | Orth. mmm (2/m 2/m 2/m) : Pnnm |
8.BB.30 | Olivenite | Cu2(AsO4)(OH) | Mon. 2/m : P21/m |
8.BB.30 | Zincolibethenite | CuZn(PO4)(OH) | Orth. mmm (2/m 2/m 2/m) : Pnnm |
8.BB.30 | Zincolivenite | CuZn(AsO4)(OH) | Orth. mmm (2/m 2/m 2/m) : Pnnm |
8.BB.30 | Auriacusite | Fe3+Cu2+(AsO4)O | Orth. mmm (2/m 2/m 2/m) : Pnnm |
8.BB.35 | Paradamite | Zn2(AsO4)(OH) | Tric. 1 : P1 |
8.BB.35 | Tarbuttite | Zn2(PO4)(OH) | Tric. 1 : P1 |
8.BB.40 | Barbosalite | Fe2+Fe3+2(PO4)2(OH)2 | Mon. 2/m : P21/b |
8.BB.40 | Hentschelite | CuFe3+2(PO4)2(OH)2 | Mon. |
8.BB.40 | Lazulite | MgAl2(PO4)2(OH)2 | Mon. 2/m : P21/b |
8.BB.40 | Scorzalite | Fe2+Al2(PO4)2(OH)2 | Mon. 2/m : P21/b |
8.BB.40 | Wilhelmkleinite | ZnFe3+2(AsO4)2(OH)2 | Mon. |
8.BB.45 | Trolleite | Al4(PO4)3(OH)3 | Mon. 2/m : B2/b |
8.BB.50 | Namibite | Cu(BiO)2(VO4)(OH) | Tric. 1 : P1 |
8.BB.55 | Phosphoellenbergerite | (Mg,◻)2Mg12(PO4,PO3OH)6(PO3OH,CO3)2(OH)6 | Hex. |
8.BB.60 | Urusovite | CuAl(AsO4)O | Mon. |
8.BB.65 | Theoparacelsite | Cu3(As2O7)(OH)2 | Orth. |
8.BB.70 | Turanite | Cu5(VO4)2(OH)4 | Tric. 1 : P1 |
8.BB.75 | Stoiberite | Cu5(VO4)2O2 | Mon. |
8.BB.80 | Fingerite | Cu11(VO4)6O2 | Tric. 1 : P1 |
8.BB.85 | Averievite | Cu6(VO4)2O2Cl2 | Trig. |
8.BB.90 | Lipscombite | Fe2+Fe3+2(PO4)2(OH)2 | Tet. |
8.BB.90 | Richellite | CaFe3+2(PO4)2(OH,F)2 | Amor. |
8.BB.90 | Zinclipscombite | ZnFe3+2(PO4)2(OH)2 | Tet. 4 2 2 : P43 21 2 |
Related Minerals - Dana Grouping (8th Ed.)
41.6.4.1 | Satterlyite | (Fe2+,Mg,Fe)12(PO4)5(PO3OH)(OH,O)6 | Trig. 3m (3 2/m) : P3 1m |
Related Minerals - Hey's Chemical Index of Minerals Grouping
19.3.1 | Moraesite | Be2(PO4)(OH) · 4H2O | Mon. |
19.3.2 | Beryllonite | NaBePO4 | Mon. 2/m : P21/b |
19.3.3 | Hurlbutite | CaBe2(PO4)2 | Mon. |
19.3.4 | Hydroxylherderite | CaBe(PO4)(OH,F) | Mon. 2/m : P21/b |
19.3.5 | Glucine | CaBe4(PO4)2(OH)4 · 0.5H2O | |
19.3.6 | Fransoletite | Ca3Be2(PO4)2(HPO4)2 · 4H2O | Mon. |
19.3.7 | Uralolite | Ca2Be4(PO4)3(OH)3 · 5H2O | Mon. |
19.3.9 | Pahasapaite | Li8(Ca,Li,K)10.5Be24(PO4)24 · 38H2O | Iso. 2 3 : I2 3 |
19.3.10 | Tiptopite | K2(Na,Ca)2Li3Be6(PO4)6(OH)2 · H2O | Hex. |
19.3.11 | Gainesite | Na(Na,K)(Be,Li)Zr2(PO4)4 · 1.5-2H2O | Tet. 4mm : I41md |
19.3.12 | Roscherite | Ca2Mn2+5Be4(PO4)6(OH)4 · 6H2O | Mon. 2/m : B2/m |
19.3.13 | Faheyite | Be2Mn2+Fe3+2(PO4)4 · 6H2O | Trig. 3 2 : P31 2 1 |
19.3.14 | Farringtonite | Mg3(PO4)2 | Mon. 2/m |
19.3.16 | Althausite | Mg4(PO4)2(OH,O)(F,☐) | Orth. mmm (2/m 2/m 2/m) : Pnma |
19.3.17 | Newberyite | Mg(HPO4) · 3H2O | Orth. mmm (2/m 2/m 2/m) : Pbca |
19.3.18 | Phosphorrösslerite | Mg(HPO4) · 7H2O | Mon. 2/m : P2/b |
19.3.19 | Bobierrite | Mg3(PO4)2 · 8H2O | Mon. 2/m : B2/b |
19.3.20 | Barićite | (Mg,Fe)3(PO4)2 · 8H2O | Mon. 2/m : B2/m |
19.3.21 | Panethite | (Na,Ca)2(Mg,Fe2+)2(PO4)2 | Mon. 2/m : P21/b |
19.3.22 | Dittmarite | (NH4)Mg(PO4) · H2O | Orth. |
19.3.23 | Struvite | (NH4)Mg(PO4) · 6H2O | Orth. mm2 |
19.3.24 | Hannayite | (NH4)2Mg3H4(PO4)4 · 8H2O | Tric. 1 : P1 |
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.
References for Holtedahlite
Reference List:
Sort by Year (asc) | by Year (desc) | by Author (A-Z) | by Author (Z-A)
Raade, G., Tyssedal, M. (1975) Althausite, a new mineral from Modum, Norway. Lithos: 8: 215-219. [as an unidentified Ca-Mg-phospate]
Raade, G., Mladeck, M.H. (1979) Holtedahlite, a new magnesium phosphate from Modum, Norway. Lithos: 12: 283-287.
Fleischer, M., Cabri, L.J., Chao, G.Y., Pabst, A. (1980) New mineral names. American Mineralogist: 65: 808-814.
Rømming, C., Raade, G. (1989) The crystal structure of natural and syntetic holtedahlite. Mineralogy and Petrology: 40: 91-100.
Jambor, J.L., Grew, E.S. (1990) New mineral names. American Mineralogist: 75: 931-937.
Evans, R.J., Groat, L.A. (2012) Structure and topology of dumortierite and dumortierite-like materials. The Canadian Mineralogist: 50: 1197-1231.
Internet Links for Holtedahlite
mindat.org URL:
https://www.mindat.org/min-1924.html
Please feel free to link to this page.
Please feel free to link to this page.
External Links:
Mineral Dealers:
Localities for Holtedahlite
Locality List




All localities listed without proper references should be considered as questionable.
Norway (TL) | |
| Raade, G. (1979): Holtedahlite, a new magnesium phospate from Modum, Norway. LITHOS 12, 283-287 + [AmMin 86:1536] |
Tingelstadtjern Quarry, Modum, Buskerud, Norway