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Stanfieldite
A valid IMA mineral species
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About Stanfieldite
Stanley Fields 1934
Formula:
Ca4Mg5(PO4)6
formula likely to be modified (Britvin et al 2020) to: Ca7M2Mg9(PO4)12 (where M denotes Ca, Mg and Fe); see below for details
Colour:
Amber to pale red
Hardness:
4½ - 5
Specific Gravity:
3.15
Crystal System:
Monoclinic
Name:
Named after Stanley Field, Chairman, Board of Trustees, Field Museum of Natural History, USA (born May 13, 1875, Manchester England; died Chicago Oct. 28, 1964)
Type Locality:
Possibly represents more than a single species:
- "~Ca7(CaMg)Mg9(PO4)12 ≡ Ca4Mg5(PO4)6", that is, the "Mindat Formula" (Brahin and lots of other meteorites)
- Ca7Mg2Mg9(PO4)12 for material from Lunar "rusty rock" 66095 (Britvin et al. 2020).
- "~Ca7(CaMg)Mg9(PO4)12 ≡ Ca4Mg5(PO4)6", that is, the "Mindat Formula" (Brahin and lots of other meteorites)
- Ca7Mg2Mg9(PO4)12 for material from Lunar "rusty rock" 66095 (Britvin et al. 2020).
Unique Identifiers
Mindat ID:
3745
Long-form identifier:
mindat:1:1:3745:3
IMA Classification of Stanfieldite
Approved
Approval year:
1966
First published:
1967
Classification of Stanfieldite
8.AC.70
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.:
38.3.5.1
38.3.5.1
38 : ANHYDROUS NORMAL PHOSPHATES, ARSENATES, AND VANADATES
3 : (AB)3(XO4)2
38 : ANHYDROUS NORMAL PHOSPHATES, ARSENATES, AND VANADATES
3 : (AB)3(XO4)2
19.12.45
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.
| Symbol | Source | Reference for Standard |
|---|---|---|
| Stf | 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 Stanfieldite
Transparency:
Transparent
Colour:
Amber to pale red
Comment:
pale bluish if weathered;
Hardness:
4½ - 5 on Mohs scale
Density:
3.15(1) g/cm3 (Measured) 3.15 g/cm3 (Calculated)
Optical Data of Stanfieldite
Type:
Biaxial (+)
RI values:
nα = 1.594 - 1.619 nβ = 1.596 - 1.622 nγ = 1.604 - 1.631
2V:
Measured: 50° to 60°, Calculated: 54° to 62°
Max. Birefringence:
δ = 0.010 - 0.012
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:
r < v
Chemistry of Stanfieldite
Mindat Formula:
Ca4Mg5(PO4)6
formula likely to be modified (Britvin et al 2020) to: Ca7M2Mg9(PO4)12 (where M denotes Ca, Mg and Fe); see below for details
formula likely to be modified (Britvin et al 2020) to: Ca7M2Mg9(PO4)12 (where M denotes Ca, Mg and Fe); see below for details
Element Weights:
Elements listed:
Crystallography of Stanfieldite
Crystal System:
Monoclinic
Cell Parameters:
a = 17.16(3) Å, b = 10.00(2) Å, c = 22.88(4) Å
β = 100.52°
β = 100.52°
Ratio:
a:b:c = 1.716 : 1 : 2.288
Unit Cell V:
3,860.21 ų (Calculated from Unit Cell)
Z:
8
Comment:
Point Group: 2/m or m.; Space Group: P2/c or Pc.
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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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) |
|---|---|---|---|---|---|---|---|
| 0015640 | Stanfieldite | Dickens B, Brown W E (1971) The crystal structure of Ca7Mg9(Ca,Mg)2(PO4)12 Tschermaks Mineralogische und Petrographische Mitteilungen 16 79-104 | 1971 | synthetic | 0 | 293 |
CIF Raw Data - click here to close
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 2.817 Å | (10) |
| 3.747 Å | (8) |
| 2.505 Å | (8) |
| 3.845 Å | (6) |
| 8.31 Å | (5) |
| 6.01 Å | (5) |
| 1.870 Å | (4) |
Geological Environment
Paragenetic Mode(s):
| Paragenetic Mode | Earliest Age (Ga) |
|---|---|
| Stage 2: Planetesimal differentiation and alteration | 4.566-4.550 |
| 5 : Primary asteroid phases | 4.566–4.560 |
| Stage 10b: Anthropogenic minerals | <10 Ka |
| 56 : Slag and smelter minerals (see also #51 and #55) | |
| 57 : Other minerals formed by human processes |
Type Occurrence of Stanfieldite
Place of Conservation of Type Material:
Masses of the Estherville meteorite are at: The Natural History Museum, London, England; Natural History Museum, Paris, France; Natural History Museum, Vienna, Austria; Field Museum of Natural History, Chicago, Illinois; Harvard University, Cambridge, Massachusetts; National Museum of Natural History, Washington, D.C., USA.
Geological Setting of Type Material:
Stony-iron meteorites
Associated Minerals at Type Locality:
Synonyms of Stanfieldite
Other Language Names for Stanfieldite
Common Associates
Associations Based on Photo Data:
| 2 photos of Stanfieldite associated with Chromite | Fe2+Cr3+2O4 |
| 2 photos of Stanfieldite associated with Troilite | FeS |
| 1 photo of Stanfieldite associated with Farringtonite | Mg3(PO4)2 |
| 1 photo of Stanfieldite associated with 'Kamacite' | (Fe,Ni) |
| 1 photo of Stanfieldite associated with Native Iron | Fe |
| 1 photo of Stanfieldite associated with Olivine Group | M2SiO4 |
| 1 photo of Stanfieldite associated with Enstatite | Mg2Si2O6 |
| 1 photo of Stanfieldite associated with Taenite | (Ni,Fe) |
| 1 photo of Stanfieldite associated with Hematite | Fe2O3 |
| 1 photo of Stanfieldite associated with Schreibersite | (Fe,Ni)3P |
Related Minerals - Strunz-mindat Grouping
| 8.AC. | 'Crocobelonite-1M' | CaFe3+2O(PO4)2 |
| 8.AC. | Magnesioqingheiite | Na2Mg(MgAl)(PO4)3 |
| 8.AC. | Manganobadalovite | NaNaMn(MgFe3+)(AsO4)3 |
| 8.AC. | Yakubovichite | CaNi2Fe3+(PO4)3 |
| 8.AC. | Changesite-(Y) | (Ca8Y)◻Fe2+(PO4)7 |
| 8.AC. | Babunaite-(Nd) | NdAsO4 |
| 8.AC. | Crocobelonite | CaFe3+2O(PO4)2 |
| 8.AC. | Wopmayite | Ca6Na3◻Mn(PO4)3(PO3OH)4 |
| 8.AC. | Beershevaite | CaFe3+3(PO4)3O |
| 8.AC. | Epiebnerite | (NH4)Zn(PO4) |
| 8.AC. | Ebnerite | (NH4)Zn(PO4) |
| 8.AC.X | Dyrnaesite-(La) | Na8Ce4+(La,REE)2(PO4)6 |
| 8.AC. | Edtollite | K2NaCu5Fe3+O2(AsO4)4 |
| 8.AC. | Angarfite | NaFe3+5(PO4)4(OH)4 · 4H2O |
| 8.AC. | Kabalovite | Fe2+3Fe3+4(PO4)6 |
| 8.AC. | Nazarchukite | Ca2NiFe3+2(PO4)4 |
| 8.AC. | Calciohatertite | NaNaCa(CaFe3+)(AsO4)3 |
| 8.AC. | Alumoedtollite | K2NaCu5AlO2(AsO4)4 |
| 8.AC.02 | Grigorievite | Cu3Fe3+2Al2(VO4)6 |
| 8.AC.02 | Koksharovite | CaMg2Fe3+4(VO4)6 |
| 8.AC.02 | Ziminaite | Fe3+ 6 (VO4)6 |
| 8.AC.05 | Hatertite | Na2(Ca,Na)(Fe3+,Cu)2(AsO4)3 |
| 8.AC.05 | Erikapohlite | Cu3(Zn,Cu,Mg)4Ca2(AsO4)6 · 2H2O |
| 8.AC.05 | 'Unnamed (Na-Mg Arsenate Hydroxyarsenate)' | NaMg3(AsO4)(AsO3OH)2 |
| 8.AC.05 | 'Unnamed (Na-Zn-H Arsenate Hydroxyarsenate)' | Na(Na0.6Zn0.4)Zn2(H0.6AsO4)(AsO3OH)2 |
| 8.AC.05 | Calciojohillerite | NaCaMg3(AsO4)3 |
| 8.AC.05 | Magnesiohatertite | (Na,Ca)2Ca(Mg,Fe3+)2(AsO4)3 |
| 8.AC.05 va | 'Alluaudite-Na[]' | ◻4Na4Mn2+4Fe3+8(PO4)12 |
| 8.AC.05 va | 'Alluaudite-Ca[]' | ◻4Ca4Mn2+4Fe3+8(PO4)12 |
| 8.AC.05 va | 'Ferroalluaudite-NaNa' | Na4Na4Fe2+4Fe3+8(PO4)12 |
| 8.AC.05 | 'Hagendorfite-NaNa' | NaNaFe2+(Mn2+,Mn3+)(PO4)3 (?) |
| 8.AC.05 | O'Danielite | Na(Zn,Mg)3(AsO4)(AsO3OH)2 |
| 8.AC.05 | Howardevansite | NaCuFe2(VO4)3 |
| 8.AC.05 | Khrenovite | Na3Fe3+2(AsO4)3 |
| 8.AC.05 | Zincobradaczekite | NaZn2Cu2(AsO4)3 |
| 8.AC.05 | Paraberzeliite | NaCa2Mg2(AsO4)3 |
| 8.AC.05 | Badalovite | Na2Mg2Fe(AsO4)3 |
| 8.AC.05 | Magnesiocanutite | NaMnMg2[AsO4]2[AsO2(OH)2] |
| 8.AC.05 | Manganohatertite | NaNaCa(MnFe3+)(AsO4)3 |
| 8.AC.05 | Camanchacaite | NaCaMg2[AsO4][AsO3(OH)]2 |
| 8.AC.07 | Zhanghuifenite | Na3Mn4Mg2Al(PO4)6 |
| 8.AC.07 | Ferrobobfergusonite | Na2Fe2+5Fe3+Al(PO4)6 |
| 8.AC.10 | Hagendorfite | NaCaMn2+Fe2+2(PO4)3 |
| 8.AC.10 | 'Ferrohagendorfite' | NaCaFe2+Fe2+2(PO4)3 |
| 8.AC.10 | Johillerite | Na(Mg,Zn)3Cu(AsO4)3 |
| 8.AC.10 | Varulite | NaCaMn2+Mn2+2(PO4)3 |
| 8.AC.10 | Nickenichite | Na0.8Ca0.4Cu0.4(Mg,Fe)3(AsO4)3 |
| 8.AC.10 | Arseniopleite | NaCaMnMn2(AsO4)3 |
| 8.AC.10 | Groatite | NaCaMn2(PO4)[PO3(OH)]2 |
| 8.AC.10 | Alluaudite | (Na,Ca)Mn2+(Fe3+,Mn2+,Fe2+,Mg)2(PO4)3 |
| 8.AC.10 | Bradaczekite | NaCu4(AsO4)3 |
| 8.AC.10 | Caryinite | (Na,Pb)(Ca,Na)CaMn2+2(AsO4)3 |
| 8.AC.10 | Ferroalluaudite | (Na,Ca)Fe2+(Fe3+,Mn2+,Fe2+)2(PO4)3 |
| 8.AC.10 | Maghagendorfite | (Na,◻)MgMn2+(Fe2+,Fe3+)2(PO4)3 |
| 8.AC.15 | Ferrowyllieite | (Na,Ca,Mn)(Fe,Mn)(Fe,Fe,Mg)Al(PO4)3 |
| 8.AC.15 | Qingheiite | NaNaMn2+(MgAl)(PO4)3 |
| 8.AC.15 | Rosemaryite | (Na,Ca,Mn)(Mn,Fe2+)(Fe3+,Mg)Al(PO4)3 |
| 8.AC.15 | Ferroqingheiite | NaNaFe2+(MgAl)(PO4)3 |
| 8.AC.15 | Ferrorosemaryite | ◻NaFe2+Fe3+Al(PO4)3 |
| 8.AC.15 | Bobfergusonite | Na2Mn5FeAl(PO4)6 |
| 8.AC.15 | Wyllieite | (Na,Ca,Mn)(Mn,Fe)(Fe,Mg)Al(PO4)3 |
| 8.AC.17 | Czochralskiite | Na4Ca3Mg(PO4)4 |
| 8.AC.18 | Manitobaite | Na16Mn2+ 25Al8(PO4)30 |
| 8.AC.20 | Marićite | NaFe2+(PO4) |
| 8.AC.25 | Schäferite | (NaCa2)Mg2(VO4)3 |
| 8.AC.25 | Berzeliite | (NaCa2)Mg2(AsO4)3 |
| 8.AC.25 | Matyhite | Ca18(Ca,◻)2Fe2+2(PO4)14 |
| 8.AC.25 | Hedegaardite | (Ca,Na)9(Ca,Na)Mg(PO4)6(PO3OH) |
| 8.AC.25 | Manganberzeliite | (NaCa2)Mn2+2(AsO4)3 |
| 8.AC.25 | Palenzonaite | (NaCa2)Mn2+2(VO4)3 |
| 8.AC.30 | Brianite | Na2CaMg(PO4)2 |
| 8.AC.35 | Vitusite-(Ce) | Na3(Ce,La,Nd)(PO4)2 |
| 8.AC.40 | Bario-olgite | (Ba,Sr)(Na,Sr,REE)2Na(PO4)2 · |
| 8.AC.40 | Olgite | (Sr,Ba)(Na,Sr,REE)2Na(PO4)2 |
| 8.AC.45 | Magnesiochangesite-(Ce) | (Ca8Ce)◻Mg(PO4)7 |
| 8.AC.45 | Tuite | Ca3(PO4)2 |
| 8.AC.45 | Ferromerrillite | Ca9NaFe2+(PO4)7 |
| 8.AC.45 | Strontiowhitlockite | Sr9Mg(PO4)6(PO3OH) |
| 8.AC.45 | Magnesiochangesite-(Y) | (Ca8Y)◻ Mg(PO4)7 |
| 8.AC.45 | Changesite-(Ce) | (Ca8Ce)◻Fe2+(PO4)7 |
| 8.AC.45 | Merrillite | Ca9NaMg(PO4)7 |
| 8.AC.45 | Whitlockite | Ca9Mg(PO4)6(PO3OH) |
| 8.AC.47 | Iwateite | Na2BaMn(PO4)2 |
| 8.AC.47 | Ozerovaite | Na2KAl3(AsO4)4 |
| 8.AC.47 | Yurmarinite | Na7(Fe3+,Mg,Cu)4(AsO4)6 |
| 8.AC.47 | Pansnerite | K3Na3(Fe3+,Al)6(AsO4)8 |
| 8.AC.47 | Anatolyite | Na6(Ca,Na)(Mg,Fe3+)3Al(AsO4)6 |
| 8.AC.50 | Fillowite | Na3CaMn2+11(PO4)9 |
| 8.AC.50 | Galileiite | Na3Fe2+Fe2+11(PO4)9 |
| 8.AC.50 | Johnsomervilleite | Na3CaFe11(PO4)9 |
| 8.AC.50 | Xenophyllite | Na4Fe2+7(PO4)6 |
| 8.AC.50 | Udinaite | NaMg4(VO4)3 |
| 8.AC.50 | Arsenudinaite | NaMg4(AsO4)3 |
| 8.AC.50 | Chladniite | Na3CaMg11(PO4)9 |
| 8.AC.52 | Lasnierite | (Ca,Sr)(Mg,Fe2+)2Al(P[O,F]4)3 |
| 8.AC.55 | Pharmazincite | KZnAsO4 |
| 8.AC.57 | Zubkovaite | Ca3Cu3(AsO4)4 |
| 8.AC.60 | Kosnarite | KZr2(PO4)3 |
| 8.AC.65 | Panethite | (Na,Ca)2(Mg,Fe2+)2(PO4)2 |
| 8.AC.75 | Ronneburgite | K2MnV4O12 |
| 8.AC.80 | Tillmannsite | Ag3Hg[(V,As)O4] |
| 8.AC.85 | Filatovite | K(Al,Zn)2(As,Si)2O8 |
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 Stanfieldite
mindat.org URL:
https://www.mindat.org/min-3745.html
Please feel free to link to this page.
Please feel free to link to this page.
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External Links:
Mineral Dealers:
References for Stanfieldite
Reference List:
Fuchs, L. H. (1967) Stanfieldite: A New Phosphate Mineral from Stony-Iron Meteorites. Science, 158 (3803). 910-911 doi:10.1126/science.158.3803.910
Localities for Stanfieldite
Showing 19 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 | |
| Schneider et al. (2013) |
Belarus | |
| Dymkin et al. (1984) +1 other reference |
Canada | |
| Davis et al. (1989, March) +1 other reference |
Chile | |
| Fuchs (1967) +1 other reference |
China | |
| Grossman (1997) +1 other reference |
Germany | |
| Neumair et al. (2016) |
Israel | |
| Britvin et al. (2021) +1 other reference |
Japan | |
| Buseck et al. (1984) |
Jordan | |
| Galuskin et al. (2023) |
Kenya | |
| Wallace et al. (2018) |
Mexico | |
| Fuchs (1967) +1 other reference |
Norway | |
| Fuchs (1967) +1 other reference |
Russia | |
| Zaslavskaya et al. (1991, March) |
| Sharygin et al. (2006) +1 other reference |
USA | |
| Fuchs (1967) +2 other references |
| Fuchs (1967) +3 other references |
| Davis et al. (1989, March) +1 other reference |
| Fuchs (1967) +2 other references |
| Fuchs (1967) +2 other references |
Quick NavTopAbout StanfielditeUnique IdentifiersIMA Classification Classification Mineral SymbolsPhysical Properties Optical Data Chemistry Crystallography Crystal StructureX-Ray Powder DiffractionGeological EnvironmentType Occurrence SynonymsOther LanguagesCommon AssociatesStrunz-MindatOther InformationInternet Links References Localities Locality List
Finmarken meteorite, Porsanger, Troms og Finnmark, Norway