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Jahnsite-(NaFeMg)

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Tip Top Mine (Tip Top pegmatite), Fourmile, Custer District, Custer Co., South Dakota, USA

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Formula:
NaFe
3+
 
Mg
 
2
Fe
3+
2
(PO
 
4
)
 
4
(OH)
 
2
 · 8H
 
2
O
System:Monoclinic
Member of:Jahnsite Group


Jahnsite Group.

Classification of Jahnsite-(NaFeMg)

IMA status:Approved 2007
Nickel-Strunz 10th (pending) edition ID:8.DH.15

8 : PHOSPHATES, ARSENATES, VANADATES
D : Phosphates, etc. with additional anions, with H2O
H : With large and medium-sized cations, (OH, etc.):RO4 < 1:1
Dana 8th edition ID:42.11.2.6

42 : HYDRATED PHOSPHATES, ETC.CONTAINING HYDROXYL OR HALOGEN
11 : (AB)3(XO4)2Zq·xH2O
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Type Occurrence of Jahnsite-(NaFeMg)

Type Locality:Tip Top Mine (Tip Top pegmatite), Fourmile, Custer District, Custer Co., South Dakota, USA

Crystallography of Jahnsite-(NaFeMg)

Crystal System:Monoclinic
Class (H-M):2/m - Prismatic
Space Group:P2/b {P1 1 2/b} {P2/c} {P1 2/c 1}{P2/a}
Space Group Setting:P2/a
Cell Parameters:a = 15.0811(16) Å, b = 7.1403(8) Å, c = 9.8299(11) Å
β = 110.445(1)°
Ratio:a:b:c = 2.112 : 1 : 1.377
Unit Cell Volume:V 991.84 ų (Calculated from Unit Cell)
Z:2
X-Ray Powder Diffraction:
d-spacingIntensity
9.218 (100)
4.884 (25)
3.537 (25)
2.973 (25)
2.854 (20)
2.819 (70)
2.593 (25)
1.933 (20)

Optical Data of Jahnsite-(NaFeMg)

Type:Biaxial (-)
RI values: nα = 1.632(1) nβ = 1.669(1) nγ = 1.671(1)
2V:Measured: 25° (5), Calculated: 26°
Maximum Birefringence:δ = 0.039

Chart shows birefringence interference colour range (at 30µm thickness) and does not take into account mineral colouration.
Surface Relief:Moderate
Dispersion:r > v, very strong
Pleochroism:Visible
Comments:X = colorless, Y and Z = beige; Y = Z > X.

Chemical Properties of Jahnsite-(NaFeMg)

Formula:
NaFe
3+
 
Mg
 
2
Fe
3+
2
(PO
 
4
)
 
4
(OH)
 
2
 · 8H
 
2
O
Essential elements:Fe, H, Mg, Na, O, P
All elements listed in formula:Fe, H, Mg, Na, O, P

Relationship of Jahnsite-(NaFeMg) to other Species

Member of:Jahnsite Group
Other Members of Group:

- +
Jahnsite-(CaFeFe)
{Ca}{Fe
2+
 
}{Fe
2+
2
}{Fe
3+
2
}(PO
 
4
)
 
4
(OH)
 
2
 · 8H
 
2
O
Jahnsite-(CaMnFe)
{Ca}{Mn
2+
 
}{Fe
2+
2
}{Fe
3+
2
}(PO
 
4
)
 
4
(OH)
 
2
 · 8H
 
2
O
Jahnsite-(CaMnMg)
{Ca}{Mn
2+
 
}{(Mg,Fe
2+
 
)
 
2
}{Fe
3+
2
}(PO
 
4
)
 
4
(OH)
 
2
 · 8H
 
2
O
Jahnsite-(CaMnMn)
{Ca}{Mn
2+
 
}{Mn
2+
2
}{Fe
3+
2
}(PO
 
4
)
 
4
(OH)
 
2
 · 8H
 
2
O
Jahnsite-(MnMnMn)
{Mn
2+
 
}{Mn
2+
 
}{Mn
2+
2
}{Fe
3+
2
}(PO
 
4
)
 
4
(OH)
 
2
 · 8H
 
2
O
Jahnsite-(NaMnMg)
{Na}{Mn
3+
 
}{Mg
 
2
}{Fe
3+
2
}(PO
 
4
)
 
4
(OH)
 
2
 · 8H
 
2
O
Keckite
CaMn
2+
 
Fe
3+
2
Fe
3+
2
(PO
 
4
)
 
4
(OH)
 
3
(H
 
2
O)
 
7
Related Minerals - Nickel-Strunz Grouping):

- +
8.DH.05Minyulite
KAl
 
2
(PO
 
4
)
 
2
(OH,F) · 4H
 
2
O
8.DH.10Leucophosphite
KFe
3+
2
(PO
 
4
)
 
2
(OH) · 2H
 
2
O
8.DH.10Spheniscidite
(NH
 
4
,K)(Fe
3+
 
,Al)
 
2
(PO
 
4
)
 
2
(OH) · 2H
 
2
O
8.DH.10Tinsleyite
KAl
 
2
(PO
 
4
)
 
2
(OH) · 2H
 
2
O
8.DH.15Jahnsite-(CaMnFe)
{Ca}{Mn
2+
 
}{Fe
2+
2
}{Fe
3+
2
}(PO
 
4
)
 
4
(OH)
 
2
 · 8H
 
2
O
8.DH.15Jahnsite-(CaMnMg)
{Ca}{Mn
2+
 
}{(Mg,Fe
2+
 
)
 
2
}{Fe
3+
2
}(PO
 
4
)
 
4
(OH)
 
2
 · 8H
 
2
O
8.DH.15Jahnsite-(CaMnMn)
{Ca}{Mn
2+
 
}{Mn
2+
2
}{Fe
3+
2
}(PO
 
4
)
 
4
(OH)
 
2
 · 8H
 
2
O
8.DH.15Keckite
CaMn
2+
 
Fe
3+
2
Fe
3+
2
(PO
 
4
)
 
4
(OH)
 
3
(H
 
2
O)
 
7
8.DH.15Rittmannite
{(Mn
2+
 
,Ca)}{Mn
2+
 
}{(Fe
2+
 
,Mn
2+
 
,Mg)
 
2
}{(Al,Fe
3+
 
)
 
2
}(PO
 
4
)
 
4
(OH)
 
2
 · 8H
 
2
O
8.DH.15Whiteite-(CaFeMg)
{Ca}{(Fe
2+
 
,Mn
2+
 
)}{Mg
 
2
}{Al
 
2
}(PO
 
4
)
 
4
(OH)
 
2
 · 8H
 
2
O
8.DH.15Whiteite-(CaMnMg)
{Ca}{Mn
2+
 
}{Mg
 
2
}{Al
 
2
}(PO
 
4
)
 
4
(OH)
 
2
 · 8H
 
2
O
8.DH.15Whiteite-(MnFeMg)
{(Mn
2+
 
,Ca)}{(Fe
2+
 
,Mn
2+
 
)}{Mg
 
2
}{Al
 
2
}(PO
 
4
)
 
4
(OH)
 
2
 · 8H
 
2
O
8.DH.15Jahnsite-(MnMnMn)
{Mn
2+
 
}{Mn
2+
 
}{Mn
2+
2
}{Fe
3+
2
}(PO
 
4
)
 
4
(OH)
 
2
 · 8H
 
2
O
8.DH.15Kaluginite
(Mn
2+
 
,Ca)MgFe
3+
 
(PO
 
4
)
 
2
(OH) · 4H
 
2
O
8.DH.15Jahnsite-(CaFeFe)
{Ca}{Fe
2+
 
}{Fe
2+
2
}{Fe
3+
2
}(PO
 
4
)
 
4
(OH)
 
2
 · 8H
 
2
O
8.DH.15Jahnsite-(NaMnMg)
{Na}{Mn
3+
 
}{Mg
 
2
}{Fe
3+
2
}(PO
 
4
)
 
4
(OH)
 
2
 · 8H
 
2
O
8.DH.15Jahnsite-(CaMgMg)
{Ca}{Mg}{Mg
 
2
}{Fe
3+
2
}(PO
 
4
)
 
4
(OH)
 
2
 · 8H
 
2
O
8.DH.20Manganosegelerite
(Mn
2+
 
,Ca)(Mn
2+
 
,Fe
2+
 
,Mg)Fe
3+
 
(PO
 
4
)
 
2
(OH)
 
2
 · 4H
 
2
O
8.DH.20Overite
CaMgAl(PO
 
4
)
 
2
(OH) · 4H
 
2
O
8.DH.20Segelerite
Ca
 
2
 Mg
 
2
 Fe
3+
2
(PO
 
4
)
 
4
(OH)
 
2
 · 8H
 
2
O
8.DH.20Wilhelmvierlingite
CaMnFe
3+
 
(PO
 
4
)
 
2
(OH) · 2H
 
2
O
8.DH.20Juonniite
CaMgSc(PO
 
4
)
 
2
(OH) · 4H
 
2
O
8.DH.25Calcioferrite
Ca
 
2
Fe
3+
2
(PO
 
4
)
 
3
(OH) · 7H
 
2
O
8.DH.25Kingsmountite
Ca
 
4
(Fe
2+
 
,Mn
2+
 
)Al
 
4
(PO
 
4
)
 
6
(OH)
 
4
 · 12H
 
2
O
8.DH.25Montgomeryite
Ca
 
4
MgAl
 
4
(PO
 
4
)
 
6
(OH)
 
4
 · 12H
 
2
O
8.DH.25Zodacite
Ca
 
4
Mn
2+
 
Fe
3+
4
(PO
 
4
)
 
6
(OH)
 
4
 · 12H
 
2
O
8.DH.30Arseniosiderite
Ca
 
2
Fe
3+
3
(AsO
 
4
)
 
3
O
 
2
 · 3H
 
2
O
8.DH.30Kolfanite
Ca
 
2
Fe
3+
2
(AsO
 
4
)
 
3
O
 
2
 · 2H
 
2
O
8.DH.30Mitridatite
Ca
 
2
Fe
3+
3
(PO
 
4
)
 
3
O
 
2
 · 3H
 
2
O
8.DH.30Pararobertsite
Ca
 
2
Mn
3+
3
(PO
 
4
)
 
3
O
 
2
 · 3H
 
2
O
8.DH.30Robertsite
Ca
 
3
Mn
3+
4
(PO
 
4
)
 
4
(OH)
 
6
 · 3H
 
2
O
8.DH.30Sailaufite
(Ca,Na,☐)
 
2
Mn
3+
3
(AsO
 
4
)
 
2
(CO
 
3
)O
 
2
 · 3H
 
2
O
8.DH.35Mantienneite
KMg
 
2
Al
 
2
Ti(PO
 
4
)
 
4
(OH)
 
3
 · 15H
 
2
O
8.DH.35Paulkerrite
K(Mg,Mn
2+
 
)
 
2
(Fe
3+
 
,Al,Ti,Mg)
 
2
Ti(PO
 
4
)
 
4
(OH)
 
3
 · 15H
 
2
O
8.DH.35Benyacarite
(H
 
2
O,K)
 
2
(Mn
2+
 
,Fe
2+
 
)
 
2
(Fe
3+
 
,Ti)
 
2
Ti(PO
 
4
)
 
4
(O,F)
 
2
 · 14H
 
2
O
8.DH.40Xanthoxenite
Ca
 
4
Fe
3+
2
(PO
 
4
)
 
4
(OH)
 
2
 · 3H
 
2
O
8.DH.45Mahnertite
NaCu
 
3
(AsO
 
4
)
 
2
Cl · 5H
 
2
O
8.DH.50Andyrobertsite
KCdCu
 
5
(AsO
 
4
)
 
4
(H
 
2
AsO
 
4
) · 2H
 
2
O
8.DH.50Calcioandyrobertsite
KCaCu
 
5
(AsO
 
4
)
 
4
(H
 
2
AsO
 
4
) · 2H
 
2
O
8.DH.55Englishite
K
 
3
Na
 
2
Ca
 
10
Al
 
15
(PO
 
4
)
 
21
(OH)
 
7
 · 26H
 
2
O
8.DH.60Bouazzerite
Bi
 
6
(Mg,Co)
 
11
Fe
3+
14
(AsO
 
4
)
 
18
(OH)
 
4
O
 
12
 · 86H
 
2
O

Other Names for Jahnsite-(NaFeMg)

Synonyms:
IMA2007-016
Other Languages:
German:Jahnsit-(NaFeMg)

Other Information

Health Warning:No information on health risks for this material has been entered into the database. You should always treat mineral specimens with care.

References for Jahnsite-(NaFeMg)

Reference List:

- +
A.R. Kampf, I.M. Steele, & T.A. Loomis (2008): Jahnsite-(NaFeMg), a new mineral from the Tip Top mine, custer County, South Dakota: Description and crystal structure. Am. Mineral. 93, 940-945.

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    • Localities for Jahnsite-(NaFeMg)

    The map shows a selection of localities that have latitude and longitude coordinates recorded. Click on the symbol to view information about a locality. The symbol next to localities in the list can be used to jump to that position on the map.
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    (TL) indicates type locality. ? indicates mineral may be doubtful at this locality. All other localities listed without reference should be considered as uncertain and unproven until references can be found.
    USA
     
    • South Dakota
      • Custer Co.
        • Custer District
          • Fourmile
    		Am.Min. 93,940-945(2008)
    Mineral and/or Locality
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    Copyright © Jolyon Ralph and Ida Chau 1993-2012. Site Map. Locality, mineral & photograph data are the copyright of the individuals who submitted them. Further information contact the Site hosted & developed by Jolyon Ralph. Mindat.org is an online information resource dedicated to providing free mineralogical information to all. Mindat relies on the contributions of hundreds of members and supporters. Mindat does not offer minerals for sale. If you would like to add information to improve the quality of our database, then click here to register.
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