Iwakiite Mineral Data

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General Iwakiite Information

Chemical Formula:

Mn++(Fe+++,Mn+++)2O4

Composition:

Molecular Weight = 229.99 gm

Manganese 40.61 % Mn 30.84 % MnO / 24.03 % Mn₂O₃

Iron 31.57 % Fe 40.61 % FeO

Oxygen 27.83 % O

______ ______

100.00 % 95.48 % = TOTAL OXIDE

Empirical Formula:

Mn²⁺Fe²⁺_1.3Mn³⁺_0.7O₄

Environment:

Regionally metamorphosed bedded manganese deposit.

IMA Status:

Approved IMA 1979

Locality:

Gozaisho mine, Iwaki, Fukushima Prefecture, Japan. Link to MinDat.org Location Data.

Name Origin:

Named for the locality.

Name Pronunciation:

Iwakiite

Synonym:

ICSD 76612

PDF 38-430

alpha vrendenbergite

vrendenbergite alpha

Iwakiite Image

Images:

Iwakiite

Comments: Back fine-grained granular iwakiite in pink rhodonite.
Location: Gazaisho Mine, Iwaki, Fukushima, Japan. Scale: See Photo.
© Jeff Weissman / Photographic Guide to Mineral Species

Iwakiite Crystallography

Axial Ratios:

a:c = 1:1.00246

Cell Dimensions:

a = 8.519, c = 8.54, Z = 8; V = 619.78 Den(Calc)= 4.93

Crystal System:

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

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

By Intensity(I/I_o): 2.57(1), 1.506(0.4), 3.016(0.4),

Crystal Structure:

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Jarosch D , Zeitschrift fur Kristallographie , 185 (1988) p.605-605, Crystal structure of iwakiite, Locality: Gozaisho mine, Fukushima Prefecture, Japan, Note: coordinates from ICSD, reproduce reported bond lengths

Physical Properties of Iwakiite

Cleavage:

None

Color:

Greenish black.

Density:

4.85

Diaphaneity:

Opaque

Habit:

Aggregates - Made of numerous individual crystals or clusters.

Habit:

Anhedral Grains - Granular minerals without the expression of crystal shapes

Hardness:

6-6.5 - Orthoclase-Pyrite

Luster:

Metallic

Magnetism:

Strongly magnetic

Streak:

black

Optical Properties of Iwakiite

Optical Data:

Uniaxial (?).

NCalc= 2.03 - from Gladstone-Dale relationship (KC = 0.2094) where Ncalc=Dcalc*KC+1
NCalc= 2.02 - from Gladstone-Dale relationship (KC = 0.2094) where Ncalc=Dmeas*KC+1

RL Anisotrophism:

Moderate, yellowish to brownish gray.

RL Color:

Light olive gray.

Reflectivity

**Standardized Intensity (100%) Reflection Spectra of Iwakiite in Air**
λ	R₁	R₂	∑ R₁(λ)	∑ R₂(λ)
420 nm	20.00	19.40
440 nm	19.90	19.30
460 nm	20.30	19.50
480 nm	20.40	19.60
500 nm	20.80	19.80
520 nm	21.20	20.10
540 nm	21.40	20.30
560 nm	21.30	20.40
580 nm	21.20	20.10
600 nm	21.00	20.00
620 nm	20.90	19.70
640 nm	20.50	19.60
660 nm	20.40	19.20
680 nm	20.20	19.10

**Calculated Relative Intensity Colors of Iwakiite in Air**
Relative Intensity	0%	50%	100%	150%	200%	250%	300%	350%	400%	450%
R₁
R₂

Calculated Properties of Iwakiite

Electron Density:

Bulk Density (Electron Density)=4.64 gm/cc
note: Specific Gravity of Iwakiite =4.93 gm/cc.

Fermion Index:

Fermion Index = 0.006825684
Boson Index = 0.993174316

Photoelectric:

PE_Iwakiite= 20.39 barns/electron
U=PE_Iwakiite x rElectron Density= 94.68 barns/cc.

Radioactivity:

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

Iwakiite Classification

Dana Class:

07.02.06.02 (07)Multiple Oxides

(07.02)(A+ B++)2 X4 Spinel group

(07.02.06)Dana Group

07.02.06.01 Kusachiite CuBi2O4 P 4/ncc 4/m 2/m 2/m

07.02.06.02 Iwakiite Mn(Fe,Mn)2O4 P 4₁/nnm 4/m 2/m 2/m

Strunz Class:

04.BB.10 04 - OXIDES (Hydroxides, V[5,6] vanadates, arsenites, antimonites, bismuthites, sulfites, selenites, tellurites, iodate

04.B - Metal:Oxygen = 3:4 and similar

04.BB -With only medium-sized cations

04.BB.10 Hausmannite MnMn2O4 I 4₁/amd 4/m 2/m 2/m

04.BB.10 Iwakiite Mn(Fe,Mn)2O4 P 4₁/nnm 4/m 2/m 2/m

04.BB.10 Hydrohetaerolite Zn2Mn4O8•(H2O) I 4₁/amd 4/m 2/m 2/m

04.BB.10 Hetaerolite ZnMn2O4 I 4₁/amd 4/m 2/m 2/m

Other Iwakiite Information

References:

NAME( AntBidBlaNic3) PHYS. PROP.(Enc. of Minerals,2nd ed.,1990) OPTIC PROP.(AntBidBlaNic3)

See Also:

Links to other databases for Iwakiite :
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 - MinDAT
10 - Mineralienatlas (Deutsch)
11 - Online Mineral Museum
12 - QUT Mineral Atlas
13 - Ruff.Info

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Print or Cut-and-Paste your Iwakiite Specimen Label here :

Iwakiite

Mn++(Fe+++,Mn+++)2O4
Dana No: 07.02.06.02 Strunz No: 04.BB.10
Locality:

Notes: