Grischunite Mineral Data

General Grischunite Information

Chemical Formula:

NaCa2Mn++5Fe+++(AsO4)6•2(H2O)

Composition:

Molecular Weight = 1,303.23 gm

Sodium 1.76 % Na 2.38 % Na₂O

Calcium 6.15 % Ca 8.61 % CaO

Manganese 21.08 % Mn 27.22 % MnO

Iron 4.29 % Fe 6.13 % Fe₂O₃

Arsenic 34.49 % As 52.91 % As₂O₅

Hydrogen 0.31 % H 2.76 % H₂O

Oxygen 31.92 % O

______ ______

100.00 % 100.00 % = TOTAL OXIDE

Empirical Formula:

NaCa₂Mn²⁺₅Fe³⁺(AsO₄)₆•2(H₂O)

Environment:

Alteration product of sarkinite in a manganese deposit.

IMA Status:

Approved IMA 1984

Locality:

Falotta mine, Oberhalbstein, Graub¨unden, Switzerland. Link to MinDat.org Location Data.

Name Origin:

Named from the former Romansch name Grischun for Graubunden Canton.

Name Pronunciation:

Grischunite + Pronunciation

Synonym:

ICSD 63431

PDF 38-387

Grischunite Image

Images:

Grischunite

Comments: Red-brown prismatic grischunite crystals on matrix.
Location: Falotta, Tinzen, Oberhalbstein, GraubÃ¼nden, Switzerland. Scale: Specimen Size 1.5x2 cm.
© Diederik Visser

Grischunite Crystallography

Axial Ratios:

a:b:c =0.9531:1:0.8932

Cell Dimensions:

a = 12.855, b = 13.487, c = 12.047, Z = 4; V = 2,088.65 Den(Calc)= 4.14

Crystal System:

Orthorhombic - DipyramidalH-M Symbol (2/m 2/m 2/m) Space Group: Pcab

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

By Intensity(I/I_o): 2.839(1), 3.15(0.9), 3.015(0.8),

Crystal Structure:

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drag2 - RMB Resize/Rotate
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Bianchi R , Pilati T , Mannucci G , American Mineralogist , 72 (1987) p.1225-1229, Crystal structure of grischunite

Physical Properties of Grischunite

Cleavage:

{???} Perfect

Color:

Dark reddish brown.

Density:

3.8

Hardness:

5 - Apatite

Luster:

Vitreous (Glassy)

Streak:

brown

Optical Properties of Grischunite

Gladstone-Dale:

CI meas= -0.086 (Poor) - where the CI = (1-KPDmeas/KC)
CI calc= 0.004 (Superior) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.1899,KPDmeas= 0.2069,KC= 0.1906
Ncalc = 1.72 - 1.79

Optical Data:

Biaxial (+), a=1.784, b=1.785, g=1.79, bire=0.0060, 2V(Calc)=50, 2V(Meas)=40-50.

Calculated Properties of Grischunite

Electron Density:

Bulk Density (Electron Density)=3.89 gm/cc
note: Specific Gravity of Grischunite =4.14 gm/cc.

Fermion Index:

Fermion Index = 0.0011451898
Boson Index = 0.9988548102

Photoelectric:

PE_Grischunite= 31.47 barns/electron
U=PE_Grischunite x rElectron Density= 122.38 barns/cc.

Radioactivity:

GRapi = 0 (Gamma Ray American Petroleum Institute Units)
Grischunite is Not Radioactive

Grischunite Classification

Dana Class:

40.02.11.01 (40)Hydrated Phosphates, etc

(40.02)where A++ (B++)2 (XO4) · x(H2O)

(40.02.11)Dana Group

40.02.11.01 Grischunite NaCa2Mn5Fe(AsO4)6•2(H2O) Pcab 2/m 2/m 2/m

Strunz Class:

08.CF.05 08 - PHOSPHATES, ARSENATES, VANADATES

08.C - Phosphates without Additional Anions, with H2O

08.CF -With large and medium-sized cations, RO4:H2O > 1:1

08.CF.05 Grischunite NaCa2Mn5Fe(AsO4)6•2(H2O) Pcab 2/m 2/m 2/m

08.CF.05 Wicksite NaCa2(Fe,Mn)4MgFe(PO4)6•2(H2O) P bca 2/m 2/m 2/m

08.CF.05 Bederite! ([],Na)Ca2(Mn,Mg,Fe)2(Fe,Mg,Al)2Mn2(PO4)6•2(H2O) Pcab 2/m 2/m 2/m

08.CF.05 Tassieite! (Na,[])Ca2(Mg,Fe,Fe)2(Fe,Mg)2(Fe,Mg)2(PO4)6(H2O)2 P bca 2/m 2/m 2/m

Other Grischunite Information

References:

NAME( AntBidBlaNic4) PHYS. PROP.(Enc. of Minerals,2nd ed.,1990) OPTIC PROP.(Enc. of Minerals,2nd ed.,1990)

See Also:

Links to other databases for Grischunite :
1 - Am. Min. Crystal Structure Database
2 - Athena
3 - EUROmin Project
4 - Ecole des Mines de Paris
5 - GeoScienceWorld
6 - Google Images
7 - Google Scholar
8 - Handbook of Mineralogy (MinSocAm)
9 - Handbook of Mineralogy (UofA)
10 - MinDAT
11 - Mineralienatlas (Deutsch)
12 - Online Mineral Museum
13 - QUT Mineral Atlas
14 - Ruff.Info
15 - WWW-MINCRYST

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Ask about Grischunite here :
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Print or Cut-and-Paste your Grischunite Specimen Label here :

Grischunite

NaCa2Mn++5Fe+++(AsO4)6•2(H2O)
Dana No: 40.02.11.01 Strunz No: 08.CF.05
Locality:

Notes: