Jahnsite-(CaMnMn) Mineral Data

General Jahnsite-(CaMnMn) Information

Chemical Formula:

CaMn++Mn++2Fe+++2(PO4)4(OH)2•8(H2O)

Composition:

Molecular Weight = 874.61 gm

Calcium 4.58 % Ca 6.41 % CaO

Manganese 18.84 % Mn 24.33 % MnO

Iron 12.77 % Fe 18.26 % Fe₂O₃

Phosphorus 14.17 % P 32.46 % P₂O₅

Hydrogen 2.07 % H 18.54 % H₂O

Oxygen 47.56 % O

______ ______

100.00 % 100.00 % = TOTAL OXIDE

Empirical Formula:

CaMn²⁺Mn²⁺₂Fe³⁺₂(PO₄)₄(OH)₂•8(H₂O)

IMA Status:

Approved IMA 1990

Locality:

Mangualde pegmatite, Beira, Portugal. 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-(CaMnMn)

Synonym:

IMA1987-020

Jahnsite-(CaMnMn) Image

Images:

Jahnsite-(CaMnMn)

Comments: Brown grains of jahnsite-(CaMnMn) in matrix.
Location: Bendada Quarry, Belmonte, Beira Alta, Portugal. Scale: Picture size 1 cm.
© Tom Loomis / Dakota Matrix

Jahnsite-(CaMnMn) Crystallography

Axial Ratios:

a:b:c =2.0815:1:1.3934

Cell Dimensions:

a = 14.887, b = 7.152, c = 9.966, Z = 2; beta = 109.77° V = 998.55 Den(Calc)= 2.91

Crystal System:

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

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

By Intensity(I/I_o): 9.4(1), 2.87(0.8), 4.704(0.3),

Physical Properties of Jahnsite-(CaMnMn)

Cleavage:

None

Color:

Brownish yellow.

Density:

2.78

Diaphaneity:

Transparent

Hardness:

4 - Fluorite

Luster:

Vitreous (Glassy)

Streak:

white

Optical Properties of Jahnsite-(CaMnMn)

Gladstone-Dale:

CI meas= 0.02 (Excellent) - where the CI = (1-KPDmeas/KC)
CI calc= 0.064 (Fair) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.226,KPDmeas= 0.2366,KC= 0.2413
Ncalc = 1.67 - 1.7

Optical Data:

Biaxial (-), a=1.643, b=1.659, g=1.671, bire=0.0280, 2V(Calc)=80, 2V(Meas)=80-81.

Calculated Properties of Jahnsite-(CaMnMn)

Electron Density:

Bulk Density (Electron Density)=2.75 gm/cc
note: Specific Gravity of Jahnsite-(CaMnMn) =2.78 gm/cc.

Fermion Index:

Fermion Index = 0.0030006706
Boson Index = 0.9969993294

Photoelectric:

PE_{Jahnsite-(CaMnMn)}= 9.76 barns/electron
U=PE_{Jahnsite-(CaMnMn)} x rElectron Density= 26.87 barns/cc.

Radioactivity:

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

Jahnsite-(CaMnMn) Classification

Dana Class:

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

(42.11)where (AB)4 (XO4)3 Zq ï¿½ x(H2O)

(42.11.02)Jahnsite Group

42.11.02.01 Jahnsite-(CaMnMg) CaMnMg2Fe2(PO4)4(OH)2•8(H2O) P 2/a 2/m

42.11.02.02 Jahnsite-(CaMnFe) CaMnFe2Fe2(PO4)4(OH)2•8(H2O) P 2/a 2/m

42.11.02.03 Jahnsite-(CaMnMn) CaMnMn2Fe2(PO4)4(OH)2•8(H2O) P 2/a 2/m

42.11.02.04 Jahnsite-(MnMnMn)* MnMnMn2Fe2(PO4)4(OH)2•8(H2O) 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-(CaMnMn) Information

References:

NAME( Dana8) PHYS. PROP.(Dana8) OPTIC PROP.(Am.Min.,Vol.75,p401-404,1990)

See Also:

Links to other databases for Jahnsite-(CaMnMn) :
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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Print or Cut-and-Paste your Jahnsite-(CaMnMn) Specimen Label here :

Jahnsite-(CaMnMn)

CaMn++Mn++2Fe+++2(PO4)4(OH)2•8(H2O)
Dana No: 42.11.02.03 Strunz No: 08.DH.15
Locality:

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