Jahnsite-(MnMnMn) Mineral Data

Jahnsite-(MnMnMn) Mineral Data +

General Jahnsite-(MnMnMn) Information

Chemical Formula:

MnMnMn2Fe+++2(PO4)4(OH)2·8(H2O)

Composition:

Molecular Weight = 889.47 gm

Manganese 24.71 % Mn 31.90 % MnO

Iron 12.56 % Fe 17.95 % Fe₂O₃

Phosphorus 13.93 % P 31.92 % P₂O₅

Hydrogen 2.04 % H 18.23 % H₂O

Oxygen 46.77 % O

______ ______

100.00 % 100.00 % = TOTAL OXIDE

Empirical Formula:

Mn²⁺Mn²⁺Mn²⁺₂Fe³⁺₂(PO₄)₄(OH)₂·8(H₂O)

IMA Status:

Not Approved IMA 1990

Locality:

Stewart mine, Pala, San Diego County, California, USA. 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.

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Jahnsite-(MnMnMn) Crystallography

Axial Ratios:

a:b:c =2.0774:1:2.5933

Cell Dimensions:

a = 15.02, b = 7.23, c = 18.75, Z = 4; beta = 100.42° V = 2,002.57 Den(Calc)= 2.95

Crystal System:

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

Physical Properties of Jahnsite-(MnMnMn)

Cleavage:

None

Color:

Brown, Purplish brown, Yellow, Yellow orange.

Diaphaniety:

Transparent to Translucent

Hardness:

4 - Fluorite

Luster:

Vitreous - Adamantine

Streak:

white

Optical Properties of Jahnsite-(MnMnMn)

Gladstone-Dale:

CI calc= 0.018 (Superior) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.2355,KC= 0.2398

Optical Data:

Biaxial (-), a=1.682, b=1.695, g=1.707, bire=0.0250

Calculated Properties of Jahnsite-(MnMnMn)

Electron Density:

r_electron=2.91 gm/cc
note: r_{Jahnsite-(MnMnMn)}=2.95 gm/cc.

Fermion Index

Fermion Index = 0.00288
Boson Index = 0.99712

Photoelectric:

PE_{Jahnsite-(MnMnMn)}= 10.64 barns/electron
U=PE_{Jahnsite-(MnMnMn)} x r_electron= 30.90 barns/cc.

Radioactivity:

GRapi = 0 (Gamma Ray American Petroleum Institute Units)

Jahnsite-(MnMnMn) is Not Radioactive

Jahnsite-(MnMnMn) Classification

Dana Class:

42.11.2.4 (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.29-75 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-(MnMnMn) Information

References:

NAME( Dana8) PHYS. PROP.(Dana8) OPTIC PROP.(Dana8)

See Also:

Links to other databases for Jahnsite-(MnMnMn) :
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-(MnMnMn) Specimen Label here :

Jahnsite-(MnMnMn)

MnMnMn2Fe+++2(PO4)4(OH)2·8(H2O)
Dana No: 42.11.2.4 Strunz No: VII/D.29-75
Locality:

Notes: