Manjiroite Mineral Data

Manjiroite Mineral Data +

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General Manjiroite Information

Chemical Formula:

(Na,K)(Mn++++,Mn++)8O16·n(H2O)

Composition:

Molecular Weight = 739.94 gm

Potassium 1.06 % K 1.27 % K₂O

Sodium 2.17 % Na 2.93 % Na₂O

Manganese 57.91 % Mn 2.88 % MnO / 88.12 % MnO₂

Aluminum 0.36 % Al 0.69 % Al₂O₃

Hydrogen 0.44 % H 3.90 % H₂O

Oxygen 38.06 % O

______ ______

100.00 % 99.78 % = TOTAL OXIDE

Empirical Formula:

Na_0.7K_0.2Mn⁴⁺_7.5Mn²⁺_0.3Al_0.1O₁₆·1.6(H₂O)

Environment:

Oxidation zone of metamorphosed bedded manganese deposits.

IMA Status:

Approved IMA 1967

Locality:

Kohare, Tachikawa, Kotamagawa, Kawai, and Takinosawa mines, Iwate Prefecture, Japan. Link to MinDat.org Location Data.

Name Origin:

Named for Manjiro Watanabe (1891-?), Emeritus Professor of Mineralogy, Tohoku University, Sendai, Japan.

Manjiroite Image

Images:

Manjiroite

Comments: Dark brownish black massive sample of manjiroite.
Location: Arizona, USA. Scale: 3.8 X 5.6 cm.
© John Veevaert

Manjiroite Crystallography

Axial Ratios:

a:c = 1:0.28882

Cell Dimensions:

a = 9.916, c = 2.864, Z = 1; V = 281.61 Den(Calc)= 4.36

Crystal System:

Tetragonal - DipyramidalH-M Symbol (4/m) Space Group: I 4/m

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

By Intensity(I/I_o): 2.406(1), 7.017(0.98), 3.136(0.92),

Physical Properties of Manjiroite

Cleavage:

None

Color:

Brownish gray, Gray brown, Dark brown gray.

Density:

4.29

Diaphaniety:

Opaque

Fracture:

Conchoidal - Fractures developed in brittle materials characterized by smoothly curving surfaces, (e.g. quartz).

Habit:

Massive - Uniformly indistinguishable crystals forming large masses.

Hardness:

7 - Quartz

Luster:

Earthy (Dull)

Streak:

brownish black

Optical Properties of Manjiroite

Optical Data:

NCalc= 2.61 - from Gladstone-Dale relationship (KC = 0.3699) where Ncalc=Dcalc*KC+1
NCalc= 2.59 - from Gladstone-Dale relationship (KC = 0.3699) where Ncalc=Dmeas*KC+1

Calculated Properties of Manjiroite

Electron Density:

r_electron=4.15 gm/cc
note: r_Manjiroite=4.36 gm/cc.

Fermion Index

Fermion Index = 0.00018
Boson Index = 0.99982

Photoelectric:

PE_Manjiroite= 15.26 barns/electron
U=PE_Manjiroite x r_electron= 63.28 barns/cc.

Radioactivity:

GRapi = 14.49 (Gamma Ray American Petroleum Institute Units)

Estimated Radioactivity from Manjiroite - barely detectable

Manjiroite Classification

Dana Class:

7.9.1.3 (7)Multiple Oxides

(7.9)where A B (O)2

(7.9.1)Cryptomelane Group (Hard black, fine-grained)

7.9.1.1 Hollandite Ba(Mn,Mn)8O16 I2/m 2/m

7.9.1.2 Cryptomelane K(Mn,Mn)8O16 I2/m 2/m

7.9.1.3 Manjiroite (Na,K)(Mn,Mn)8O16·n(H2O) I 4/m 4/m

7.9.1.4 Coronadite Pb(Mn,Mn)8O16 I2/m 2/m

7.9.1.5 Strontiomelane! SrMn6Mn2O16 P 2₁/m 2/m

7.9.1.6 Henrymeyerite! BaFeTi7O16 I 4/m 4/m

Strunz Class:

IV/D.08-10 IV - Oxides

IV/D - Oxides with metal : oxygen = 1:2 (MO2 and related compounds)

IV/D.08 - Cryptomelane group

IV/D.08-10 Manjiroite (Na,K)(Mn,Mn)8O16·n(H2O) I 4/m 4/m

IV/D.08-20 Cryptomelane K(Mn,Mn)8O16 I2/m 2/m

IV/D.08-25 Strontiomelane! SrMn6Mn2O16 P 2₁/m 2/m

IV/D.08-30 Priderite (K,Ba)(Ti,Fe)8O16 I 4/m 4/m

IV/D.08-33 Henrymeyerite! BaFeTi7O16 I 4/m 4/m

IV/D.08-35 Ankangite Ba(Ti,V,Cr)8O16 I 4/m 4/m

IV/D.08-40 Mannardite BaTi6V2O16·(H2O) I 4₁/a 4/m

IV/D.08-50 Redledgeite BaTi6Cr2O16·(H2O) I 4₁/a 4/m

IV/D.08-60 Hollandite Ba(Mn,Mn)8O16 I2/m 2/m

IV/D.08-70 Coronadite Pb(Mn,Mn)8O16 I2/m 2/m

IV/D.08-80 Cesarolite PbH2Mn3O8 HEX-R Trig

Other Manjiroite Information

References:

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

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Manjiroite

(Na,K)(Mn++++,Mn++)8O16·n(H2O)
Dana No: 7.9.1.3 Strunz No: IV/D.08-10
Locality:

Notes: