Bannisterite Mineral Data

General Bannisterite Information

Chemical Formula:

KCa(Mn,Fe++,Zn,Mg)21(Si,Al)32O76(OH)16•4-12(H2O)

Composition:

Molecular Weight = 3,734.70 gm

Potassium 0.84 % K 1.01 % K₂O

Sodium 0.12 % Na 0.17 % Na₂O

Calcium 0.97 % Ca 1.35 % CaO

Magnesium 1.89 % Mg 3.13 % MgO

Manganese 17.95 % Mn 23.17 % MnO

Aluminum 2.17 % Al 4.10 % Al₂O₃

Zinc 3.68 % Zn 4.58 % ZnO

Iron 5.23 % Fe 5.58 % FeO / 1.28 % Fe₂O₃

Silicon 21.43 % Si 45.85 % SiO₂

Hydrogen 1.09 % H 9.74 % H₂O

Oxygen 44.64 % O

______ ______

100.00 % 99.96 % = TOTAL OXIDE

Empirical Formula:

K_0.8Na_0.2Ca_0.9Mn²⁺_12.2Fe²⁺_2.9Mg_2.9Zn_2.1Fe³⁺_0.6Si_28.5Al₃O₇₆(OH)₁₆ï¿½12.2(H₂O)

Environment:

Metamorphosed Mn-Zn orebodies.

IMA Status:

Valid Species (Pre-IMA) 1936

Locality:

In the Banallt mine, Rhiw, Lleyn Peninsula, Wales. Link to MinDat.org Location Data.

Name Origin:

Named for Dr. Frederick Allen Bannister (1901-?), formerly Keeper of Minerals, British Museum (Natural History), London, England.

Name Pronunciation:

Bannisterite + Pronunciation

Synonym:

ICSD 80078

PDF 46-1281

Bannisterite Image

Images:

Bannisterite

Comments: Deep red micaceous bannisterite.
Location: Zinc Mine, Broken Hill, New South Wales, Australia. Scale: See Photo.
© Jeff Weissman / Photographic Guide to Mineral Species

Bannisterite Crystallography

Axial Ratios:

a:b:c =1.3602:1:1.507

Cell Dimensions:

a = 22.265, b = 16.368, c = 24.668, Z = 4; beta = 94.285° V = 8,964.72 Den(Calc)= 2.77

Crystal System:

Monoclinic - Prismatic H-M Symbol (2/m) Space Group: A2/a

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

By Intensity(I/I_o): 12.33(1), 3.44(0.2), 4.1(0.16),

Physical Properties of Bannisterite

Cleavage:

{001} Perfect, {???} Distinct

Color:

Dark brown, Black.

Density:

2.83 - 2.84, Average = 2.83

Diaphaneity:

Translucent

Habit:

Aggregates - Made of numerous individual crystals or clusters.

Habit:

Bladed - Aggregates of thin lath-like crystals (e.g. kyanite).

Habit:

Prismatic - Crystals Shaped like Slender Prisms (e.g. tourmaline).

Hardness:

4 - Fluorite

Luster:

Resinous

Optical Properties of Bannisterite

Gladstone-Dale:

CI meas= 0.042 (Good) - where the CI = (1-KPDmeas/KC)
CI calc= 0.02 (Excellent) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.2116,KPDmeas= 0.2067,KC= 0.2158
Ncalc = 1.6 - 1.61

Optical Data:

Biaxial (?), a=1.544-1.574, b=1.586-1.611, g=1.589-1.612, bire=0.0380-0.0450, 2V(Calc)=18-28, 2V(Meas)=small. Dispersion r < v moderate.

Calculated Properties of Bannisterite

Electron Density:

Bulk Density (Electron Density)=2.73 gm/cc
note: Specific Gravity of Bannisterite =2.77 gm/cc.

Fermion Index:

Fermion Index = 0.01
Boson Index = 0.99

Photoelectric:

PE_Bannisterite= 8.99 barns/electron
U=PE_Bannisterite x r_electron= 24.57 barns/cc.

Radioactivity:

GRapi = 11.93 (Gamma Ray American Petroleum Institute Units)
Concentration of Bannisterite per GRapi unit = 8.39 (%)

Estimated Radioactivity from Bannisterite - barely detectable

Bannisterite Classification

Dana Class:

74.01.01.04 (74)Phyllosilicate Modulated Layers

(74.01)with joined islands

(74.01.01)Stilpnomelane group

74.01.01.01 Stilpnomelane K(Fe,Mg,Fe)8(Si,Al)12(O,OH)27•n(H2O) P1 1

74.01.01.02 Lennilenapeite K6-7(Mg,Mn,Fe,Fe,Zn)48(Si,Al)72(O,OH)216•16(H2O) Unk (pseudo-HEX) Tri

74.01.01.03 Franklinphilite (K,Na)4(Mn,Mg,Zn)48(Si,Al)72(O,OH)216•6(H2O) pseudo-HEX P1 or P1 Tri

74.01.01.04 Bannisterite KCa(Mn,Fe,Zn,Mg)21(Si,Al)32O76(OH)16•4-12(H2O) A2/a 2/m

74.01.01.05 Middendorfite! K3Na2Mn5Si12(O,OH)36•2H2O P 2₁/m or P 2₁ Mono

Strunz Class:

09.EG.75 09 - SILICATES (Germanates)

09.E - Phyllosilicates

09.EG -Double nets with 6-membered and larger rings

09.EG.75 Bannisterite KCa(Mn,Fe,Zn,Mg)21(Si,Al)32O76(OH)16•4-12(H2O) A2/a 2/m

Other Bannisterite Information

References:

NAME( AntBidBlaNic2) PHYS. PROP.(Enc. of Minerals,2nd ed.,1990) OPTIC PROP.(AntBidBlaNic2)

See Also:

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

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Bannisterite

KCa(Mn,Fe++,Zn,Mg)21(Si,Al)32O76(OH)16•4-12(H2O)
Dana No: 74.01.01.04 Strunz No: 09.EG.75
Locality:

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