Birnessite Mineral Data

[How the Club Works] [Memberships - Junior, Deluxe , and Platinum] [FAQ] [Past Minerals]
Join the Club - Junior, Deluxe and Platinum Memberships Available
High Quality Minerals Sent to Your Home or School Each Month
Mineral of the Month Club - An Inexpensive Way to Enjoy Minerals

General Birnessite Information

Chemical Formula:

(Na,Ca,K)x(Mn++++,Mn+++)2O4•1.5(H2O)

Composition:

Molecular Weight = 215.71 gm

Potassium 1.81 % K 2.18 % K₂O

Sodium 3.20 % Na 4.31 % Na₂O

Calcium 1.86 % Ca 2.60 % CaO

Manganese 50.94 % Mn 36.59 % Mn₂O₃ / 40.30 % MnO₂

Hydrogen 1.40 % H 12.53 % H₂O

Oxygen 40.79 % O

______ ______

100.00 % 98.52 % = TOTAL OXIDE

Empirical Formula:

Na_0.3Ca_0.1K_0.1Mn⁴⁺Mn³⁺O₄•1.5(H₂O)

Environment:

Found as grains cementing gravel in a road cut 30 km N of Aberdeen. Major component of desert varnish. Deep sea Mn nodules.

IMA Status:

Valid Species (Pre-IMA) 1956

Locality:

Birness, Aberdeenshire, Scotland. Link to MinDat.org Location Data.

Name Origin:

Named after the locality.

Name Pronunciation:

Birnessite + Pronunciation

Synonym:

ICSD 68916

PDF 23-1046

Birnessite Image

Images:

Birnessite

Comments: Gray birnessite. Very small crystals on massive material.
Location: Das Aufgeklärte Glück Mine, Hasserode, Wernigerode, Harz Mts, Saxony-Anhalt, Germany. Scale: Picture size 7 mm.
© Thomas Witzke / Abraxas-Verlag

Images:

Birnessite Buserite

Comments: Round, "rabbit pellets" of buserite which dehydrates to birnessite when dry. Image photographed through water which is needed to preserve this species.
Location: Aomori Springs, Oppu, Japan. Scale: Sphere size 7 mm.
© Dave Barthelmy

Birnessite Crystallography

Axial Ratios:

a:b:c =1.8154:1:2.574

Cell Dimensions:

a = 5.174, b = 2.85, c = 7.336, Z = 1; beta = 103.18° V = 105.33 Den(Calc)= 3.40

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): 7.27(1), 1.41(0.7), 2.44(0.7),

Crystal Structure:

Mouse
drag1 - LMB Manipulate Structure
drag2 - RMB Resize/Rotate
Keyboard
S - Stereo Pair on/off
H - Help Screen
I - Data Info
A - Atoms On/Off
P - Polyhedra On/Off
B - Bonds On/Off
Help on Above

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

View Additional jPOWD Structure files for Birnessite
[1] [2]

Physical Properties of Birnessite

Color:

Dark brown, Black.

Density:

Diaphaneity:

Subopaque

Habit:

Earthy - Dull, clay-like texture with no visible crystalline affinities, (e.g. howlite).

Habit:

Massive - Uniformly indistinguishable crystals forming large masses.

Hardness:

1.5 - Between Talc and Gypsum

Luster:

Sub Metallic

Optical Properties of Birnessite

Gladstone-Dale:

CI meas= 0.282 (Poor) - where the CI = (1-KPDmeas/KC)
CI calc= 0.366 (Poor) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.2088,KPDmeas= 0.2367,KC= 0.3294
Ncalc = 1.99 - 2.12

Optical Data:

Biaxial (?), a=1.69, g=1.73, bire=0.0400

Calculated Properties of Birnessite

Electron Density:

Bulk Density (Electron Density)=2.90 gm/cc
note: Specific Gravity of Birnessite =3.00 gm/cc.

Fermion Index:

Fermion Index = 0.0002251701
Boson Index = 0.9997748299

Photoelectric:

PE_Birnessite= 13.58 barns/electron
U=PE_Birnessite x r_electron= 39.35 barns/cc.

Radioactivity:

GRapi = 25.26 (Gamma Ray American Petroleum Institute Units)
Concentration of Birnessite per GRapi unit = 3.96 (%)

Estimated Radioactivity from Birnessite - barely detectable

Birnessite Classification

Dana Class:

07.05.03.01 (07)Multiple Oxides

(07.05)where A B X2

(07.05.03)Dana Group

07.05.03.01 Birnessite (Na,Ca,K)x(Mn,Mn)2O4•1.5(H2O) C 2/m 2/m

Strunz Class:

04.FL.45 04 - OXIDES (Hydroxides, V[5,6] vanadates, arsenites, antimonites, bismuthites, sulfites, selenites, tellurites, iodate

04.F - Hydroxides (without V or U)

04.FL -Hydroxides with H2O ± (OH); sheets of edge-sharing octahedra

04.FL.45 Birnessite (Na,Ca,K)x(Mn,Mn)2O4•1.5(H2O) C 2/m 2/m

Other Birnessite Information

References:

NAME( Dana8) PHYS. PROP.(Enc. of Minerals,2nd ed.,1990) OPTIC PROP.(Enc. of Minerals,2nd ed.,1990)

See Also:

Links to other databases for Birnessite :
1 - Alkali-Nuts(English)
2 - Alkali-Nuts(Francais)
3 - Am. Min. Crystal Structure Database
4 - Athena
5 - EUROmin Project
6 - Ecole des Mines de Paris
7 - Franklin Minerals(Dunn)
8 - Google Images
9 - Google Scholar
10 - Handbook of Mineralogy (MinSocAm)
11 - Handbook of Mineralogy (UofA)
12 - HyperPhysics
13 - MinDAT
14 - MinMax(Deutsch)
15 - MinMax(English)
16 - Mineralienatlas (Deutsch)
17 - QUT Mineral Atlas
18 - Ruff.Info
19 - WWW-MINCRYST

Search for Birnessite using:

[ALTAVISTA] [AOL] [All-The-Web] [HotBot] [Ixquick] [MAMMA] [MSN.COM] [Netscape] [Scirus] [Teoma] [Wikipedia] [YAHOO]

Visit our Advertisers for Birnessite :

AA Mineral Specimens

B & L Fine Minerals

Crystalarium.com

Dan Weinrich Fine Minerals

Dan Weinrich Auctions

Dakota Matrix

Diamond Dan Publications

John Betts Fine Minerals

Mason's Minerals

Mineral News

Mineral of the Month Club

Wrights Rock Shop

Translate Birnessite Mineral Data :

Ask about Birnessite here :
Ask-A-Mineralogist from the Mineralogical Society of America
Mindat.org's Discussion Groups
Original Rockhounds Discussion Group
Rockhounds Discussion Group on Yahoo Groups
Mineral Discussion Forum from Fabre Minerals - also available in Español

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

Birnessite

(Na,Ca,K)x(Mn++++,Mn+++)2O4•1.5(H2O)
Dana No: 07.05.03.01 Strunz No: 04.FL.45
Locality:

Notes: