Jahnsite-(CaFeFe) Mineral Data

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General Jahnsite-(CaFeFe) Information

Chemical Formula:

(Ca,Mn)(Fe++,Mn++)Fe++2Fe+++2(PO4)4(OH)2•8(H2O)

Composition:

Molecular Weight = 851.41 gm

Calcium 2.82 % Ca 3.95 % CaO

Magnesium 2.28 % Mg 3.79 % MgO

Manganese 3.87 % Mn 5.00 % MnO

Aluminum 0.32 % Al 0.60 % Al₂O₃

Iron 24.93 % Fe 16.03 % FeO / 17.82 % Fe₂O₃

Phosphorus 14.55 % P 33.34 % P₂O₅

Hydrogen 2.37 % H 21.16 % H₂O

Oxygen 48.86 % O

______ ______

100.00 % 101.69 % = TOTAL OXIDE

Empirical Formula:

Ca_0.6Mn²⁺_0.6Fe²⁺_1.9Mg_0.8Fe³⁺_1.9Al_0.1(PO₄)₄·10(H₂O)

Environment:

Pliocene-Pleistocene clay deposits in vivianite nodules and secondary phosphates.

IMA Status:

Not Approved IMA (Dana # Added)

Locality:

Hime-Shima, Oita Prefecute and Kobe, Hyogo Prefecture, western Japan. Link to MinDat.org Location Data.

Name Origin:

Named for Richard H. Jahns (1915-1983), mineralogist and pegmatite expert, Stanford University, Palo Alto, California, USA.

Name Pronunciation:

Jahnsite-(CaFeFe)

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Jahnsite-(CaFeFe) Crystallography

Axial Ratios:

a:b:c =2.0849:1:1.3802

Cell Dimensions:

a = 14.97, b = 7.18, c = 9.91, Z = 2; beta = 110.5° V = 997.72 Den(Calc)= 2.83

Crystal System:

Monoclinic - PrismaticH-M Symbol (2/m) Space Group: P 2/a

$Help on X Ray Diffraction:$ X Ray Diffraction:

By Intensity(I/I_o): 9.28(1)(001), 4.642(0.5)(002), 2.834(0.35)(302),1.947(0.15)(024,405), 3.091(0.12)(412), 5.017(0.12)(210),

Physical Properties of Jahnsite-(CaFeFe)

Color:

Dark brown.

Habit:

Aggregates - Made of numerous individual crystals or clusters.

Habit:

Encrustations - Forms crust-like aggregates on matrix.

Hardness:

4 - Fluorite

Luster:

Vitreous - Adamantine

Optical Properties of Jahnsite-(CaFeFe)

Optical Data:

NCalc= 1.7 - from Gladstone-Dale relationship (KC = 0.2462) where Ncalc=Dcalc*KC+1

Calculated Properties of Jahnsite-(CaFeFe)

Electron Density:

Bulk Density (Electron Density)=2.82 gm/cc
note: Specific Gravity of Jahnsite-(CaFeFe) =2.83 gm/cc.

Fermion Index:

Fermion Index = 0.0078441697
Boson Index = 0.9921558303

Photoelectric:

PE_{Jahnsite-(CaFeFe)}= 9.39 barns/electron
U=PE_{Jahnsite-(CaFeFe)} x rElectron Density= 26.50 barns/cc.

Radioactivity:

GRapi = 0 (Gamma Ray American Petroleum Institute Units)
Jahnsite-(CaFeFe) is Not Radioactive

Jahnsite-(CaFeFe) Classification

Dana Class:

42.11.03.05 (42)Hydrated Phosphates, etc., Containing Hydroxyl or Halogen

(42.11)where (AB)4 (XO4)3 Zq · x(H2O)

(42.11.03)Whiteite Group

42.11.03.01 Whiteite-(CaFeMg) Ca(Fe,Mn)Mg2Al2(PO4)4(OH)2•8(H2O) P 2₁/a 2/m

42.11.03.02 Whiteite-(MnFeMg) (Mn,Ca)(Fe,Mn)Mg2Al2(PO4)4(OH)2•8(H2O) P 2/a 2/m

42.11.03.03 Whiteite-(CaMnMg) CaMnMg2Al2(PO4)4(OH)2•8(H2O) P 2/a 2/m

42.11.03.04 Rittmannite MnMnFeAl2(OH)2(PO4)4•8(H2O) P 2/a 2/m

42.11.03.05 Jahnsite-(CaFeFe)! (Ca,Mn)(Fe,Mn)Fe2Fe2(PO4)4(OH)2•8(H2O) P 2/a 2/m

42.11.03.06 Jahnsite-(NaFeMg)! NaFeMg2Fe2(PO4)4(OH)2•8H2O P 2/a 2/m

42.11.03.07 Jahnsite-(CaMgMg)! CaMgMg2Fe2(PO4)4(OH)2•8H2O P 2/a 2/m

42.11.03.08 Jahnsite-(NaMnMg)! NaMnMg2Fe2(PO4)4(OH)2•8H2O P 2/a 2/m

Strunz Class:

08.DH.15 08 - PHOSPHATES, ARSENATES, VANADATES

08.D - Phosphates, etc

08.DH -With large and medium-sized cations, (OH, etc.):RO4 < 1:1

08.DH.15 Keckite Ca(Mn,Zn)2Fe3(PO4)4(OH)3•2(H2O) P 2₁/a 2/m

08.DH.15 Jahnsite-(CaMnFe) CaMnFe2Fe2(PO4)4(OH)2•8(H2O) P 2/a 2/m

08.DH.15 Jahnsite-(CaMnMg) CaMnMg2Fe2(PO4)4(OH)2•8(H2O) P 2/a 2/m

08.DH.15 Jahnsite-(CaMnMn) CaMnMn2Fe2(PO4)4(OH)2•8(H2O) P 2/a 2/m

08.DH.15 Jahnsite-(MnMnMn)* MnMnMn2Fe2(PO4)4(OH)2•8(H2O) P 2/a 2/m

08.DH.15 Kaluginite* (Mn,Ca)MgFe(PO4)2(OH)•4(H2O) C cca 2/m 2/m 2/m

08.DH.15 Rittmannite MnMnFeAl2(OH)2(PO4)4•8(H2O) P 2/a 2/m

08.DH.15 Whiteite-(MnFeMg) (Mn,Ca)(Fe,Mn)Mg2Al2(PO4)4(OH)2•8(H2O) P 2/a 2/m

08.DH.15 Whiteite-(CaFeMg) Ca(Fe,Mn)Mg2Al2(PO4)4(OH)2•8(H2O) P 2₁/a 2/m

08.DH.15 Whiteite-(CaMnMg) CaMnMg2Al2(PO4)4(OH)2•8(H2O) P 2/a 2/m

08.DH.15 Jahnsite-(CaFeFe)! (Ca,Mn)(Fe,Mn)Fe2Fe2(PO4)4(OH)2•8(H2O) P 2/a 2/m

08.DH.15 Jahnsite-(NaFeMg)! NaFeMg2Fe2(PO4)4(OH)2•8H2O P 2/a 2/m

08.DH.15 Jahnsite-(CaMgMg)! CaMgMg2Fe2(PO4)4(OH)2•8H2O P 2/a 2/m

08.DH.15 Jahnsite-(NaMnMg)! NaMnMg2Fe2(PO4)4(OH)2•8H2O P 2/a 2/m

Other Jahnsite-(CaFeFe) Information

References:

NAME( AmMin, Vol 86, p 1114) PHYS. PROP.(AmMin, Vol 86, p 1114)

See Also:

Links to other databases for Jahnsite-(CaFeFe) :
1 - Am. Min. Crystal Structure Database
2 - Athena
3 - Google Images
4 - Google Scholar
5 - MinDAT
6 - MinMax(Deutsch)
7 - MinMax(English)
8 - Mineralienatlas (Deutsch)
9 - QUT Mineral Atlas
10 - Ruff.Info

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Print or Cut-and-Paste your Jahnsite-(CaFeFe) Specimen Label here :

Jahnsite-(CaFeFe)

(Ca,Mn)(Fe++,Mn++)Fe++2Fe+++2(PO4)4(OH)2•8(H2O)
Dana No: 42.11.03.05 Strunz No: 08.DH.15
Locality:

Notes: