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Romanèchite

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Formula:
(Ba,H2O)2(Mn4+,Mn3+)5O10
System:
Monoclinic
Colour:
Greyish black, black
Lustre:
Sub-Metallic, Dull
Hardness:
5 - 6
Name:
Named after its discovery locality, Romanèche, Saône-et-Loir, France.
Chemically similar to hollandite.
May be confused with members of the Cryptomelane Group.

Visit gemdat.org for gemological information about Romanèchite.


Classification of Romanèchite

Approved, 'Grandfathered' (first described prior to 1959)
4.DK.10

4 : OXIDES (Hydroxides, V[5,6] vanadates, arsenites, antimonites, bismuthites, sulfites, selenites, tellurites, iodates)
D : Metal: Oxygen = 1:2 and similar
K : With large (+- medium-sized) cations; tunnel structures
7.9.2.1

7 : MULTIPLE OXIDES
9 : AB8X16
7.4.18

7 : Oxides and Hydroxides
4 : Oxides of Be, Mg and the alkaline earths

Physical Properties of Romanèchite

Sub-Metallic, Dull
Colour:
Greyish black, black
Streak:
Black, brown
Hardness:
5 - 6 on Mohs scale

Chemical Properties of Romanèchite

Formula:
(Ba,H2O)2(Mn4+,Mn3+)5O10

Crystallography of Romanèchite

Crystal System:
Monoclinic
Class (H-M):
2/m - Prismatic
Cell Parameters:
a = 13.929(1) Å, b = 2.8459(4) Å, c = 9.678(1) Å
β = 92.39(1)°
Ratio:
a:b:c = 4.894 : 1 : 3.401
Unit Cell V:
383.31 ų (Calculated from Unit Cell)
Z:
2
Twinning:
Sagenite-like twinning of acicular to prismatic crystals has been observed.
Comment:
Space group C2/m

X-Ray Powder Diffraction

Powder Diffraction Data:
d-spacingIntensity
3.465 (70)
2.875 (70)
2.415 (70)
2.190 (100)
1.820 (70)
1.560 (70)
1.399 (70)

Type Occurrence of Romanèchite

Common Associates

Associated Minerals Based on Photo Data:
Birnessite49 photos of Romanèchite associated with Birnessite on mindat.org.
Todorokite49 photos of Romanèchite associated with Todorokite on mindat.org.
Rhodochrosite11 photos of Romanèchite associated with Rhodochrosite on mindat.org.
Baryte11 photos of Romanèchite associated with Baryte on mindat.org.
Pyrolusite5 photos of Romanèchite associated with Pyrolusite on mindat.org.
Quartz4 photos of Romanèchite associated with Quartz on mindat.org.
Fluorite4 photos of Romanèchite associated with Fluorite on mindat.org.
Natrojarosite3 photos of Romanèchite associated with Natrojarosite on mindat.org.
Jarosite3 photos of Romanèchite associated with Jarosite on mindat.org.
Arseniosiderite3 photos of Romanèchite associated with Arseniosiderite on mindat.org.

Related Minerals - Nickel-Strunz Grouping

4.DK.05Akaganeite(Fe3+,Ni2+)8(OH,O)16Cl1.25 · nH2O
4.DK.05aCoronaditePb(Mn4+6Mn3+2)O16
4.DK.05aCryptomelaneK(Mn4+7Mn3+)O16
4.DK.05aHollanditeBa(Mn4+6Mn3+2)O16
4.DK.05aManjiroiteNa(Mn4+7Mn3+)O16
4.DK.05bMannarditeBa(Ti4+6V3+2)O16
4.DK.05bPrideriteK(Ti4+7Fe3+)O16
4.DK.05bRedledgeiteBa(Ti4+6Cr3+2)O16
4.DK.05bHenrymeyeriteBa(Ti4+7Fe2+)O16
4.DK.05aStrontiomelaneSr(Mn4+6Mn3+2)O16
4.DK.10Todorokite(Na,Ca,K,Ba,Sr)1-x(Mn,Mg,Al)6O12 · 3-4H2O

Related Minerals - Hey's Chemical Index of Minerals Grouping

7.4.1BromelliteBeO
7.4.2BehoiteBe(OH)2
7.4.3ClinobehoiteBe(OH)2
7.4.4ChrysoberylBeAl2O4
7.4.5Magnesiotaaffeite-2N’2SMg3Al8BeO16
7.4.6Magnesiotaaffeite-6N’3SMg2BeAl6O12
7.4.7PericlaseMgO
7.4.8BruciteMg(OH)2
7.4.9SpinelMgAl2O4
7.4.10MeixneriteMg6Al2(OH)16(OH)2 · 4H2O
7.4.11LimeCaO
7.4.12PortlanditeCa(OH)2
7.4.13ChlormayeniteCa12Al14O32[◻4Cl2]
7.4.14HydrocalumiteCa4Al2(OH)12(Cl,CO3,OH)2 · 4H2O
7.4.15MarokiteCaMn3+2O4
7.4.16Ranciéite(Ca,Mn2+)0.2(Mn4+,Mn3+)O2 · 0.6H2O
7.4.17HollanditeBa(Mn4+6Mn3+2)O16
7.4.19Todorokite(Na,Ca,K,Ba,Sr)1-x(Mn,Mg,Al)6O12 · 3-4H2O

Synonyms of Romanèchite

Other Language Names for Romanèchite

Varieties of Romanèchite

Skemmatite

Apparent mixture of ferroan romanechite and pyrolusite, once believed to be a direct alteration product of pyroxmangite and considered by Dana and others as a ferrian wad.

Other Information

Health Risks:
No information on health risks for this material has been entered into the database. You should always treat mineral specimens with care.

References for Romanèchite

Reference List:
Sort by Year (asc) | by Year (desc) | by Author (A-Z) | by Author (Z-A)
Turner, E. (1828): Chemical examination of the oxides of manganese. Part II. On the composition of the ores of manganese described by Mr. Haidinger. The Philosophical Magazine 4, 96-104.
Lacroix (1910): 4: 6.
Zambonini F., Cagliotti V. (1931): Nuove ricerche sulla composizione chimica della romanechite. Periodico di Mineralogia – Roma, 73-80.
Palache, Charles, Harry Berman & Clifford Frondel (1944), The System of Mineralogy of James Dwight Dana and Edward Salisbury Dana Yale University 1837-1892, Volume I: Elements, Sulfides, Sulfosalts, Oxides. John Wiley and Sons, Inc., New York. 7th edition, revised and enlarged: 670.
Turner, S. & Post, J. E. (1988): Refinement of the substructure and superstructure of romanechite. American Mineralogist 73, 1155-1161.

Internet Links for Romanèchite

mindat.org URL:
https://www.mindat.org/min-3441.html
Please feel free to link to this page.
Specimens:
The following Romanèchite specimens are currently listed for sale on minfind.com.

Localities for Romanèchite

Mineral and/or Locality  
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