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Birnessite

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Formula:
(Na,Ca)0.5(Mn4+,Mn3+)2O4 · 1.5H2O
System:
Monoclinic
Colour:
Black; dark brown in ...
Hardness:
Name:
Named in 1956 by L. H. P. Jones and Angela Alice Milne for the type locality at Birness, Scotland, UK.

Classification of Birnessite

Valid - first described prior to 1959 (pre-IMA) - "Grandfathered"
4.FL.45

4 : OXIDES (Hydroxides, V[5,6] vanadates, arsenites, antimonites, bismuthites, sulfites, selenites, tellurites, iodates)
F : Hydroxides (without V or U)
L : Hydroxides with H2O +- (OH); sheets of edge-sharing octahedra
7.5.3.1

7 : MULTIPLE OXIDES
5 : (AB)2X3
7.18.11

7 : Oxides and Hydroxides
18 : Oxides of Mn
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First Recorded Occurrence of Birnessite

Occurrences of Birnessite

Geological Setting:
A major manganese-bearing mineral of many soils; a common alteration product of manganese-rich mineral deposits; a component of bacterially-precipitated manganese oxides; an important constituent of "desert varnish" and marine manganese nodules.

Physical Properties of Birnessite

Diaphaneity (Transparency):
Opaque
Colour:
Black; dark brown in transmitted light
Hardness (Mohs):
Density:
3 g/cm3 (Measured)    3.4 g/cm3 (Calculated)

Crystallography of Birnessite

Crystal System:
Monoclinic
Class (H-M):
2/m - Prismatic
Space Group:
B2/m
Cell Parameters:
a = 5.175Å, b = 2.85Å, c = 7.337Å
β = 103.18°
Ratio:
a:b:c = 1.816 : 1 : 2.574
Unit Cell Volume:
V 105.36 ų (Calculated from Unit Cell)
Z:
1
Morphology:
Rarely in platelets, to 50 µm; commonly extremely finely crystalline, spherulitic, cellular.
X-Ray Powder Diffraction Data:
d-spacingIntensity
7.08 (100)
2.333 (43)
1.711 (29)
3.547 (28)
2.031 (24)
2.468 (17)
1.426 (17)
Comments:
Recorded on a marine nodule from the Caribbean Sea; all reflections are typically very broad.

Optical Data of Birnessite

Type:
Uniaxial (-)
RI values:
nω = 1.730 nε = 1.690
Max Birefringence:
δ = 0.040
Image shows birefringence interference colour range (at 30µm thickness) and does not take into account mineral colouration.
Surface Relief:
High
Dispersion:
weak to moderate
Comments:
The mineral is pseudo-uniaxial (-); an identification by optical properties is impossible.

Chemical Properties of Birnessite

Formula:
(Na,Ca)0.5(Mn4+,Mn3+)2O4 · 1.5H2O
Essential elements:
All elements listed in formula:
Analytical Data:
Electron microprobe analysis of a marine nodule from the Caribbean Sea; total Mn calculated as MnO2, H2O content calculated from the mass balance
SiO2   (0.9)
MnO2  (75.8)
FeO    (0.55)
CoO    (0.14)
NiO    (0.80)
CuO    (0.33)
MgO    (6.2)
CaO    (0.39)
Na2O   (1.9)
K2O    (1.8)
Cl     (0.1)
H2O   (10.89)
S      (0.2)

sum   100.00 wt.-%
Common Impurities:
Cl,Co,Cu,Fe,K,Ni,Mg,S,Si

Relationship of Birnessite to other Species

Structurally related to group(s):
4.FL.TrébeurdeniteFe22+Fe43+O2(OH)10CO3·3H2O
4.FL.05WoodalliteMg6Cr2(OH)16Cl2 · 4H2O
4.FL.05IowaiteMg6Fe23+(OH)16Cl2 · 4H2O
4.FL.05Jamborite(Ni2+1-x,Cox3+(OH)2-x(SO4)x·nH2O [x ≤ ⅓; n ≤ (1 - x)]
4.FL.05MeixneriteMg6Al2(OH)16(OH)2 · 4H2O
4.FL.05MuskoxiteMg7Fe4O13 · 10H2O
4.FL.05FougèriteFe42+Fe23+(OH)12[CO3]·3H2O
4.FL.10HydrocalumiteCa4Al2(OH)12(Cl,CO3,OH)2 · 4H2O
4.FL.15KuzeliteCa4Al2(OH)12[SO4] · 6H2O
4.FL.20Aurorite(Mn2+,Ag,Ca)Mn34+O7 · 3H2O
4.FL.20Chalcophanite(Zn,Fe,Mn)Mn3O7 · 3H2O
4.FL.20ErnienickeliteNiMn3O7 · 3H2O
4.FL.20Jianshuiite(Mg,Mn)Mn3O7 · 3H2O
4.FL.25WoodruffiteZn(Mn4+,Mn3+)5O10·3½H2O
4.FL.30Asbolane(Ni,Co)2-xMn4+(O,OH)4 · nH2O
4.FL.35BuseriteNa4Mn14O27 · 21H2O
4.FL.40Ranciéite(Ca,Mn)Mn4O9 · 3H2O
4.FL.40Takanelite(Mn,Ca)Mn4O9 · H2O
4.FL.55CianciulliiteMn(Mg,Mn)2Zn2(OH)10 · 2-4H2O
4.FL.60JenseniteCu3[TeO6] · 2H2O
4.FL.65LeisingiteCu(Mg,Cu,Fe,Zn)2[TeO6] · 6H2O
4.FL.70Akdalaite4Al2O3 · H2O
4.FL.75Cafetite(Ca,Mg)(Fe,Al)2Ti4O12 · 4H2O
4.FL.80MouriteUMo5O12(OH)10
4.FL.85DeloryiteCu4(UO2)(MoO4)2(OH)6
7.18.1ManganositeMnO
7.18.2HausmanniteMn2+Mn23+O4
7.18.3PyrolusiteMnO2
7.18.4RamsdelliteMn4+O2
7.18.5Akhtenskiteε-Mn4+O2
7.18.6FeitknechtiteMn3+O(OH)
7.18.7ManganiteMn3+O(OH)
7.18.8GroutiteMn3+O(OH)
7.18.9Nsutite(Mn4+,Mn2+)(O,OH)2
7.18.10PyrochroiteMn(OH)2
7.18.12Aurorite(Mn2+,Ag,Ca)Mn34+O7 · 3H2O
7.18.13CianciulliiteMn(Mg,Mn)2Zn2(OH)10 · 2-4H2O

Other Names for Birnessite

Name in Other Languages:
German:Birnessit
Simplified Chinese:水钠锰矿
钠水锰矿
Spanish:Birnessita

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 Birnessite

Reference List:
Jones, L. H. P. and Milne, A. A. (1956): Birnessite, a new manganese oxide mineral from Aberdeenshire, Scotland. Mineralogical Magazine 31, 283-288. - American Mineralogist (1990), 75, 477-489 (abstract).

Glover, E. D. (1977): Characterization of a marine birnessite. American Mineralogist 62, 278-285.

Chukhrov, F. V., Gorshkov, A. I., Rudnitskaya, E. S., Beresovskaya, V. V., and Sivtsov, A. V. (1980): Manganese minerals in clay: a review. Clays and Clay Minerals 28, 346-453.

Golden, D. C., Dixon, J. B. and Chen, C. C. (1986): Ion exchange, thermal transformations, and oxidizing properties of birnessite. Clays and Clay Minerals 34, 511-520.

Golden, D. C., Chen, C. C., and Dixon, J. B. (1987): Transformation of birnessite to buserite, todorokite, and manganite under mild hydrothermal treatment. Clays and Clay Minerals 35, 271-280.

Post, J. E., and Veblen, D. R. (1990): Crystal structure determinations of synthetic sodium, magnesium and potassium birnessite using TEM and the Rietveld method. American Mineralogist 75, 477-489.

Anthony, J. W. et al. (1997): Handbook of Mineralogy, Vol. 3, 58.

Lanson, B., Drits, V. A., E. Silvester, E., and Manceau, A. (2000): Structure of H-exchanged hexagonal birnessite and its mechanism of formation from Na-rich monoclinic buserite at low pH. American Mineralogist 85, 826-838.

Lanson, B., Drits, V. A., Gaillot, A., Silvester, E., Plançon, A., and Manceau, A. (2002): Structure of the heavy-metal sorbed birnessite: Part I. Results from X-ray diffraction. American Mineralogist 87, 1631-1645.

Johnson, E. A., and Post, J. E. (2006): Water in the interlayer region of birnessite: Importance in cation exchange and structural stability. American Mineralogist 91, 609-618.

Internet Links for Birnessite

Localities for Birnessite

map shows a selection of localities that have latitude and longitude coordinates recorded. Click on the symbol to view information about a locality. The symbol next to localities in the list can be used to jump to that position on the map.
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