Jahnsite-(CaMnMn) Mineral Data

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.

Synonym:

IMA1987-020

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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 - PrismaticH-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

Diaphaniety:

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

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:

r_electron=2.75 gm/cc
note: r_{Jahnsite-(CaMnMn)}=2.78 gm/cc.

Fermion Index

Fermion Index = 0.003
Boson Index = 0.997

Photoelectric:

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

Radioactivity:

GRapi = 0 (Gamma Ray American Petroleum Institute Units)

Jahnsite-(CaMnMn) is Not Radioactive

Jahnsite-(CaMnMn) Classification

Dana Class:

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

(42.11)where (AB)4 (XO4)3 Zq · x(H2O)

(42.11.2)Dana Group

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

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

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

42.11.2.4 Jahnsite-(MnMnMn)* MnMnMn2Fe2(PO4)4(OH)2·8(H2O) P 2/a 2/m

Strunz Class:

VII/D.29-70 VII - Phosphates, Arsenates and Vanadates

VII/D - Water-bearing phosphates with unfamiliar anions, cations of very big and medium size: Al, Mg and Ca, Na, K

VII/D.29 - Whiteite - Jahnsite group

VII/D.29-10 Whiteite-(CaFeMg) Ca(Fe,Mn)Mg2Al2(PO4)4(OH)2·8(H2O) P 2₁/a 2/m

VII/D.29-20 Whiteite-(CaMnMg) CaMnMg2Al2(PO4)4(OH)2·8(H2O) P 2/a 2/m

VII/D.29-30 Whiteite-(MnFeMg) (Mn,Ca)(Fe,Mn)Mg2Al2(PO4)4(OH)2·8(H2O) P 2/a 2/m

VII/D.29-40 Rittmannite MnMnFeAl2(OH)2(PO4)4·8(H2O) P 2/a 2/m

VII/D.29-50 Jahnsite-(CaMnMg) CaMnMg2Fe2(PO4)4(OH)2·8(H2O) P 2/a 2/m

VII/D.29-60 Jahnsite-(CaMnFe) CaMnFe2Fe2(PO4)4(OH)2·8(H2O) P 2/a 2/m

VII/D.29-70 Jahnsite-(CaMnMn) CaMnMn2Fe2(PO4)4(OH)2·8(H2O) P 2/a 2/m

VII/D.29-75 Jahnsite-(MnMnMn)* MnMnMn2Fe2(PO4)4(OH)2·8(H2O) P 2/a 2/m

VII/D.29-80 Keckite Ca(Mn,Zn)2Fe3(PO4)4(OH)3·2(H2O) P 2₁/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 -Google Images 4 -Google Scholar 5 -MinDAT 6 -MinMax(Deutsch) 7 -MinMax(English) 8 -Mineralienatlas (Deutsch) 9 -QUT Mineral Atlas

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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: 42.11.2.3 Strunz No: VII/D.29-70
Locality:

Notes: