Romanechite Mineral Data

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General Romanechite Information

Chemical Formula:

(Ba,H2O)2(Mn++++,Mn+++)5O10

Composition:

Molecular Weight = 544.25 gm

Barium 17.66 % Ba 19.72 % BaO

Manganese 48.45 % Mn 69.62 % Mn₂O₃

Silicon 0.52 % Si 1.10 % SiO₂

Hydrogen 0.44 % H 3.97 % H₂O

Oxygen 32.92 % O

______ ______

100.00 % 94.41 % = TOTAL OXIDE

Empirical Formula:

Ba_0.7Mn³⁺_4.8Si_0.1O₁₀•1.2(H₂O)

Environment:

Weathering product of manganese-bearing oxides, carbonates, and silicates in sedimentary deposits.

IMA Status:

Valid Species (Pre-IMA) 1910

Locality:

Romaneche, Saone-et-Loire, France. Link to MinDat.org Location Data.

Name Origin:

Named for the locality.

Name Pronunciation:

Romanechite + Pronunciation

Synonym:

Psilomelane

Romanechite Image

Images:

Romanechite

Comments: Black botryoidal romanèchite.
Location: Callenberg North (no. 2) open cut, Callenberg, Glauchau, Saxony, Germany. Scale: Specimen size 9 mm.
© Thomas Witzke / Abraxas-Verlag

Romanechite Crystallography

Axial Ratios:

a:b:c =4.8944:1:3.4006

Cell Dimensions:

a = 13.929, b = 2.8459, c = 9.678, Z = 3; beta = 92.39° V = 383.31 Den(Calc)= 7.07

Crystal System:

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

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

By Intensity(I/I_o): 2.41(1), 2.19(0.85), 3.48(0.6),

Crystal Structure:

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drag2 - RMB Resize/Rotate
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Turner S , Post J E , American Mineralogist , 73 (1988) p.1155-1161, Refinement of the substructure and superstructure of romanechite

Physical Properties of Romanechite

Cleavage:

None

Color:

Grayish black, Black, Steel gray.

Density:

6.45

Diaphaneity:

Opaque

Habit:

Acicular - Occurs as needle-like crystals.

Habit:

Botryoidal - "Grape-like" rounded forms (e.g.. malachite).

Habit:

Fibrous - Crystals made up of fibers.

Hardness:

5-6 - Between Apatite and Orthoclase

Luster:

Sub Metallic

Streak:

brown black

Optical Properties of Romanechite

Optical Data:

Biaxial (?)

NCalc= 2.77 - from Gladstone-Dale relationship (KC = 0.2506) where Ncalc=Dcalc*KC+1
NCalc= 2.62 - from Gladstone-Dale relationship (KC = 0.2506) where Ncalc=Dmeas*KC+1

RL Anisotrophism:

Strong.

RL Bireflectance:

Strong, gray to white.

RL Color:

Gray-white.

Reflectivity

**Standardized Intensity (100%) Reflection Spectra of Romanechite in Air**
λ	R₁	R₂	∑ R₁(λ)	∑ R₂(λ)
400 nm	26.70	38.70
420 nm	26.30	37.70
440 nm	25.60	35.90
460 nm	25.20	34.80
480 nm	24.80	34.00
500 nm	24.30	33.00
520 nm	23.80	32.10
540 nm	23.40	31.10
560 nm	22.90	30.10
580 nm	22.40	29.30
600 nm	22.00	28.60
620 nm	21.60	28.00
640 nm	21.30	27.50
660 nm	21.20	27.20
680 nm	20.90	26.80
700 nm	20.70	26.50

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

Calculated Properties of Romanechite

Electron Density:

Bulk Density (Electron Density)=6.56 gm/cc
note: Specific Gravity of Romanechite =7.07 gm/cc.

Fermion Index:

Fermion Index = 0.03
Boson Index = 0.97

Photoelectric:

PE_Romanechite= 89.23 barns/electron
U=PE_Romanechite x rElectron Density= 585.61 barns/cc.

Radioactivity:

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

Romanechite Classification

Dana Class:

07.09.02.01 (07)Multiple Oxides

(07.09)Dana Type

(07.09.02)Dana Group

07.09.02.00 Psilomelane? (Ba,H2O)2Mn5O10 A2/m 2/m

07.09.02.01 Romanechite (Ba,H2O)2(Mn,Mn)5O10 C 2/m 2/m

Strunz Class:

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

04.D - Metal:Oxygen = 1:2 and similar

04.DK -With large (± medium-sized) cations; tunnel structures

04.DK.10 Cryptomelane K(Mn,Mn)8O16 I2/m 2/m

04.DK.10 Todorokite (Na,Ca,K)2(Mn,Mn)6O12•3-4.5(H2O) P 2/m 2/m

04.DK.10 Romanechite (Ba,H2O)2(Mn,Mn)5O10 C 2/m 2/m

04.DK.10 Strontiomelane! SrMn6Mn2O16 P 2₁/m 2/m

Other Romanechite Information

References:

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

See Also:

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

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

Romanechite

(Ba,H2O)2(Mn++++,Mn+++)5O10
Dana No: 07.09.02.01 Strunz No: 04.DK.10
Locality:

Notes: