Pennantite Mineral Data

Pennantite Mineral Data +

General Pennantite Information

Chemical Formula:

Mn5Al(Si3Al)O10(OH)8

Composition:

Molecular Weight = 708.96 gm

Manganese 38.75 % Mn 50.03 % MnO

Aluminum 7.61 % Al 14.38 % Al₂O₃

Silicon 11.88 % Si 25.42 % SiO₂

Hydrogen 1.14 % H 10.16 % H₂O

Oxygen 40.62 % O

______ ______

100.00 % 100.00 % = TOTAL OXIDE

Empirical Formula:

Mn²⁺₅Al₂Si₃O₁₀(OH)₈

IMA Status:

Valid Species (Pre-IMA) 1946

Locality:

Link to MinDat.org Location Data.

Pennantite Image

Images:

Pennantite

Comments: Dark brown micaceous pennantite.
Location: Gambatesa Mine, Val Graveglia, Genova, Liguria, Italy. Scale: See Photo.
© Jeff Weissman / Photographic Guide to Mineral Species

Pennantite Crystallography

Axial Ratios:

a:b:c =0.5771:1:1.5238

Cell Dimensions:

a = 5.454, b = 9.45, c = 14.4, Z = 2; beta = 97.2° V = 736.33 Den(Calc)= 3.20

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): 7.1(1), 2.43(0.8), 3.57(0.8),

Physical Properties of Pennantite

Cleavage:

[001] Perfect

Color:

Orange red, Reddish brown.

Density:

3.06

Diaphaniety:

Translucent

Hardness:

2-3 - Gypsum-Calcite

Luster:

Pearly

Streak:

brownish yellow

Optical Properties of Pennantite

Gladstone-Dale:

CI meas= 0.006 (Superior) - where the CI = (1-KPDmeas/KC)
CI calc= 0.05 (Good) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.205,KPDmeas= 0.2144,KC= 0.2158

Optical Data:

Biaxial (-), a=1.646, b=1.661, g=1.661, bire=0.0150, 2V(Calc)=0, 2V(Meas)=0.

Calculated Properties of Pennantite

Electron Density:

r_electron=2.98 gm/cc
note: r_Pennantite=3.06 gm/cc.

Fermion Index

Fermion Index = 0.00574
Boson Index = 0.99426

Photoelectric:

PE_Pennantite= 10.55 barns/electron
U=PE_Pennantite x r_electron= 31.42 barns/cc.

Radioactivity:

GRapi = 0 (Gamma Ray American Petroleum Institute Units)

Pennantite is Not Radioactive

Pennantite Classification

Dana Class:

71.4.1.8 (71)Phyllosilicate Sheets of Six-Membered Rings

(71.4)interlayered 1:1, 2:1, and octahedra

(71.4.1)Chlorite group (Tri-Dioctahedral)

71.4.1.1 Donbassite Al2[Al2.33][Si3AlO10](OH)8 C 2/m 2/m

71.4.1.2 Cookeite LiAl4(Si3Al)O10(OH)8 P 2₁/a 2/m

71.4.1.3 Sudoite Mg2(Al,Fe)3Si3AlO10(OH)8 C 2/m 2/m

71.4.1.4 Clinochlore (Mg,Fe)5Al(Si3Al)O10(OH)8 C 2/m 2/m

71.4.1.5 Nimite (Ni,Mg,Fe)5Al(Si3Al)O10(OH)8 C 2/m 2/m

71.4.1.6 Baileychlore (Zn,Al,[])3[Fe2Al][Si3AlO10](OH)8 C1,C1 Tri

71.4.1.7 Chamosite (Fe,Mg,Fe)5Al(Si3Al)O10(OH,O)8 C 2/m 2/m

71.4.1.8 Pennantite Mn5Al(Si3Al)O10(OH)8 C 2/m 2/m

71.4.1.9 Orthochamosite! (Fe,Mg,Fe)5Al(Si3Al)O10(OH,O)8 C3m-pseudoHEX Ortho

71.4.1.10 Borocookeite! Li(13x)Al(4-x)(BSi3)O10(OH,F)8[x=0-0.33] pseudo C 2/m 2/m

Strunz Class:

VIII/H.23-60 VIII - Silicates

VIII/H - Phyllosilicates (layered) Mica like with [Si4O10]4- and related groups

VIII/H.23 - Chlorite group

VIII/H.23-10 Sudoite Mg2(Al,Fe)3Si3AlO10(OH)8 C 2/m 2/m

VIII/H.23-20 Clinochlore (Mg,Fe)5Al(Si3Al)O10(OH)8 C 2/m 2/m

VIII/H.23-30 Chamosite (Fe,Mg,Fe)5Al(Si3Al)O10(OH,O)8 C 2/m 2/m

VIII/H.23-40 Orthochamosite (Fe,Mg,Fe)5Al(Si3Al)O10(OH,O)8 C3m-pseudoHEX Ortho

VIII/H.23-50 Baileychlore (Zn,Al,[])3[Fe2Al][Si3AlO10](OH)8 C1,C1 Tri

VIII/H.23-60 Pennantite Mn5Al(Si3Al)O10(OH)8 C 2/m 2/m

VIII/H.23-70 Nimite (Ni,Mg,Fe)5Al(Si3Al)O10(OH)8 C 2/m 2/m

VIII/H.23-80 Gonyerite Mn3[Mn3Fe][(Si,Fe)4O10](OH,O)8 pseudo-HEX Ortho

VIII/H.23-90 Cookeite LiAl4(Si3Al)O10(OH)8 P 2₁/a 2/m

VIII/H.23-95 Borocookeite! Li(13x)Al(4-x)(BSi3)O10(OH,F)8[x=0-0.33] pseudo C 2/m 2/m

VIII/H.23-100 Manandonite Li2Al4[(Si2AlB)O10](OH)8 C1 1

VIII/H.23-110 Franklinfurnaceite Ca2(Fe,Al)MnMn3Zn2Si2O10(OH)8 C 2 2

Other Pennantite Information

References:

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

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

Pennantite

Mn5Al(Si3Al)O10(OH)8
Dana No: 71.4.1.8 Strunz No: VIII/H.23-60
Locality:

Notes: