Neltnerite Mineral Data

Neltnerite Mineral Data +

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General Neltnerite Information

Chemical Formula:

CaMn+++6SiO12

Composition:

Molecular Weight = 589.78 gm

Calcium 6.80 % Ca 9.51 % CaO

Manganese 55.89 % Mn 80.30 % Mn₂O₃

Silicon 4.76 % Si 10.19 % SiO₂

Oxygen 32.55 % O

______ ______

100.00 % 100.00 % = TOTAL OXIDE

Empirical Formula:

CaMn³⁺₆SiO₁₂

IMA Status:

Approved IMA 1982

Locality:

Link to MinDat.org Location Data.

Synonym:

ICSD 28423

PDF 35-66

Neltnerite Image

Images:

Neltnerite

Comments: Black neltnerite microcrystals lining vugs.
Location: Manganese Creek, Keeweenaw County, Michigan, USA. Scale: See Photo.
© Jeff Weissman / Photographic Guide to Mineral Species

Neltnerite Crystallography

Axial Ratios:

a:c = 1:1.99218

Cell Dimensions:

a = 9.464, c = 18.854, Z = 8; V = 1,688.70 Den(Calc)= 4.64

Crystal System:

Tetragonal - Ditetragonal DipyramidalH-M Symbol (4/m 2/m 2/m) Space Group: I 4₁/acd

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

By Intensity(I/I_o): 2.728(1), 1.672(0.85), 1.427(0.6),

Crystal Structure:

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de Villiers J P R , Dobson S M , Buseck P R , European Journal of Mineralogy , 3 (1991) p.567-573, Refinement of the crystal structure of neltnerite,, a member of the bixbyite-braunite group of minerals

Physical Properties of Neltnerite

Cleavage:

[???] Indistinct

Color:

Black.

Density:

4.63

Diaphaniety:

Opaque

Fracture:

Sub Conchoidal - Fractures developed in brittle materials characterized by semi-curving surfaces.

Hardness:

6 - Orthoclase

Luster:

Sub Metallic

Streak:

black

Optical Properties of Neltnerite

Optical Data:

NCalc= 2.31 - from Gladstone-Dale relationship (KC = 0.2829) where Ncalc=Dcalc*KC+1
NCalc= 2.31 - from Gladstone-Dale relationship (KC = 0.2829) where Ncalc=Dmeas*KC+1

Calculated Properties of Neltnerite

Electron Density:

r_electron=4.41 gm/cc
note: r_Neltnerite=4.64 gm/cc.

Fermion Index

Fermion Index = 0.00247
Boson Index = 0.99753

Photoelectric:

PE_Neltnerite= 15.62 barns/electron
U=PE_Neltnerite x r_electron= 68.81 barns/cc.

Radioactivity:

GRapi = 0 (Gamma Ray American Petroleum Institute Units)

Neltnerite is Not Radioactive

Neltnerite Classification

Dana Class:

7.5.1.2 (7)Multiple Oxides

(7.5)where A B X2

(7.5.1)Humite group (Tetragonal: I41/acd) containing Si

7.5.1.1 Braunite-I MnMn6SiO12 I 4₁/acd 4/m 2/m 2/m

7.5.1.2 Neltnerite CaMn6SiO12 I 4₁/acd 4/m 2/m 2/m

7.5.1.3 Braunite-II* MnMn6SiO12 I 4₁/acd 4/m 2/m 2/m

7.5.1.4 Abswurmbachite CuMn6SiO12 I 4₁/acd 4/m 2/m 2/m

Strunz Class:

VIII/B.09-07 VIII - Silicates

VIII/B - Nesosubsilicates, with anions unfamiliar to tetraheders, cations of octahedral and tetrahedral orientation [4/6]

VIII/B.09 - Braunite - Langbanite - Katoptrite series

VIII/B.09-03 Braunite-I MnMn6SiO12 I 4₁/acd 4/m 2/m 2/m

VIII/B.09-05 Abswurmbachite CuMn6SiO12 I 4₁/acd 4/m 2/m 2/m

VIII/B.09-07 Neltnerite CaMn6SiO12 I 4₁/acd 4/m 2/m 2/m

VIII/B.09-10* Franciscanite-III Mn6V2Si2(O,OH)14 P 3 3

VIII/B.09-10 Franciscanite-VIII Mn3(V,[])1-x(SiO4)(O,OH)3(x=0.5) P 3 3

VIII/B.09-12* Orebroite-III Mn6(Fe,Sb)2Si2(O,OH)14 P 3 3

VIII/B.09-12 Orebroite-VIII Mn3(Sb,Fe)SiO4(O,OH)3 P 3 3

VIII/B.09-14* Welinite-III Mn6(W,Mg)2Si2(O,OH)14 P 3 3

VIII/B.09-14 Welinite-VIII (Mn,Mg)3(W,Mn)1-x(SiO4)(O,OH)3(x=1/3) P 3 3

VIII/B.09-17 Langbanite (Mn,Ca,Fe)4(Mn,Fe)9SbSi2O24 C 2/m 2/m

VIII/B.09-20 Yeatmanite Mn9Zn6Sb2Si4O28 P1 1

VIII/B.09-30 Katoptrite (Mn,Mg)13(Al,Fe)4Sb2Si2O28 C 2/m 2/m

Other Neltnerite Information

References:

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

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Neltnerite

CaMn+++6SiO12
Dana No: 7.5.1.2 Strunz No: VIII/B.09-07
Locality:

Notes: