General Jahnsite-(NaFeMg) Information

Help on Chemical Formula: Chemical Formula: NaFe+++Mg2Fe+++2(PO4)4(OH)2•8H2O

Help on Composition: Composition: Molecular Weight = 780.46 gm

Sodium 2.12 % Na 2.86 % Na₂O

Calcium 0.26 % Ca 0.36 % CaO

Magnesium 6.26 % Mg 10.38 % MgO

Manganese 0.28 % Mn 0.36 % MnO

Iron 19.46 % Fe 27.83 % Fe₂O₃

Phosphorus 15.87 % P 36.37 % P₂O₅

Hydrogen 2.44 % H 21.84 % H₂O

Oxygen 53.30 % O

______ ______

100.00 % 100.00 % = TOTAL OXIDE

Help on Empirical Formula: Empirical Formula: Na_0.72Ca_0.05Mn²⁺_0.04Fe³⁺_0.72Mg_0.01Mg₂Fe³⁺₂4(P)4(O_3.77)4(OH)_0.23(OH)₂ƒL8(H₂O)

Help on Environment: Environment: Found in a single football-sized rock, consisting mainly of heterosite and presumed to be a fragment of highly altered and oxidized triphylite. Whiteite-jahnsite group.

Help on IMA Status: IMA Status: Approved IMA 2007 (Dana # Added)

Help on Locality: Locality: Tip Top mine, Custer County, South Dakota, USA. Link to MinDat.org Location Data.

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

Help on Name Pronunciation: Name Pronunciation: Jahnsite-(NaFeMg) Say JAHNSITE-(NAFEMG)

Help on Synonym: Synonym: IMA2007-016

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Jahnsite-(NaFeMg) Crystallography

Help on Axial Ratios: Axial Ratios: a:b:c =2..&checktime(1121,1,1,':').3766

Help on Cell Dimensions: Cell Dimensions: a = 15.0811, b = 7.1403, c = 9.8299, Z = 2; beta = 110.445° V = 991.84 Den(Calc)= 2.61

Help on Crystal System: 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): 9.218(1), 2.819(0.7), 2.593(0.25),2.973(0.25), 3.537(0.25), 4.884(0.25), 1.933(0.2), 2.854(0.2),

Physical Properties of Jahnsite-(NaFeMg)

Help on Color: Color: Yellow.

Help on Density: Density: 2.58

Help on Diaphaneity: Diaphaneity: Transparent

Help on Fracture: Fracture: Brittle - Splintery - Brittle fracture leaving splintery fragments.

Help on Habit: Habit: Prismatic - Crystals Shaped like Slender Prisms (e.g. tourmaline).

Help on Habit: Habit: Striated - Parallel lines on crystal surface or cleavage face.

Help on Hardness: Hardness: 4 - Fluorite

Help on Luster: Luster: Vitreous (Glassy)

Help on Streak: Streak: white

Optical Properties of Jahnsite-(NaFeMg)

Help on Gladstone-Dale: Gladstone-Dale: CI meas= 0.005 (Superior) - where the CI = (1-KPDmeas/KC)
CI calc= 0.017 (Superior) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.2519,KPDmeas= 0.2548,KC= 0.2561
Ncalc = 1.66 - 1.67

Help on Optical Data: Optical Data: Biaxial (-), a=1.632, b=1.669, g=1.671, bire=0.0390, 2V(Calc)=24, 2V(Meas)=25. Dispersion very strong, r> v.

Calculated Properties of Jahnsite-(NaFeMg)

Help on Electron Density: Electron Density: Bulk Density (Electron Density)=2.59 gm/cc
note: Specific Gravity of Jahnsite-(NaFeMg) =2.58 gm/cc.

Help on Fermion Index: Fermion Index: Fermion Index = 0.01
Boson Index = 0.99

Help on Photoelectric: Photoelectric: PE_{Jahnsite-(NaFeMg)} = 6.74 barns/electron
U=PE_{Jahnsite-(NaFeMg)} x rElectron Density= 17.46 barns/cc.

Help on Radioactivity: Radioactivity: GRapi = 0 (Gamma Ray American Petroleum Institute Units)
Jahnsite-(NaFeMg) is Not Radioactive

Jahnsite-(NaFeMg) Classification

Help on Dana Class: Dana Class: 42.11.03.06 (42)Hydrated Phosphates, etc., Containing Hydroxyl or Halogen

(42.11)where (AB)4 (XO4)3 Zq ƒL 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

Help on Strunz Class: 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-(NaFeMg) Information

Help on References: References: NAME( AmMin, v93:940) PHYS. PROP.(AmMin, v93:940) OPTIC PROP.(AmMin, v93:940)

Help on See Also: See Also: Links to other databases for Jahnsite-(NaFeMg) :
1 - Am. Min. Crystal Structure Database
2 - Athena
3 - GeoScienceWorld
4 - Google Images
5 - Google Scholar
6 - MinDAT
7 - Mineralienatlas (Deutsch)
8 - Online Mineral Museum
9 - QUT Mineral Atlas
10 - Ruff.Info

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