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

Environment:

Metamorhpic or hydrothermally altered manganese- and zinc-bearing assemblages.

IMA Status:

Valid Species (Pre-IMA) 1946

Locality:

Ty Canol incline, Benault mine, Rhiw, Carnarvonshire, Lleyn Peninsula, Gwynedd, Wales. Link to MinDat.org Location Data.

Name Origin:

Named for Thomas Pennant (1726-1798), Welsh naturalist.

Name Pronunciation:

Pennantite + Pronunciation

Synonym:

Grovesite

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 - Prismatic H-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

Diaphaneity:

Translucent

Habit:

Microscopic Crystals - Crystals visible only with microscopes.

Habit:

Rosette - Bundled tabular aggregates resembling rose flower petals.

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
Ncalc = 1.66 - 1.69

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:

Bulk Density (Electron Density)=2.98 gm/cc
note: Specific Gravity of Pennantite =3.06 gm/cc.

Fermion Index:

Fermion Index = 0.0057467392
Boson Index = 0.9942532608

Photoelectric:

PE_Pennantite= 10.55 barns/electron
U=PE_Pennantite x rElectron Density= 31.42 barns/cc.

Radioactivity:

GRapi = 0 (Gamma Ray American Petroleum Institute Units)
Pennantite is Not Radioactive

Pennantite Classification

Dana Class:

71.04.01.08 (71)Phyllosilicate Sheets of Six-Membered Rings

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

(71.04.01)Chlorite group (Tri-Dioctahedral)

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

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

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

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

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

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

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

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

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

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

Strunz Class:

09.EC.55 09 - SILICATES (Germanates)

09.E - Phyllosilicates

09.EC -Phyllosilicates with mica sheets, composed of tetrahedral and octahedral nets

09.EC.55 Donbassite Al2[Al2.33][Si3AlO10](OH)8 C 2/m 2/m

09.EC.55 Baileychlore (Zn,Al,[])3[Fe2Al][Si3AlO10](OH)8 C1,C1 Tri

09.EC.55 Clinochlore (Mg,Fe)5Al(Si3Al)O10(OH)8 C 2/m 2/m

09.EC.55 Cookeite LiAl4(Si3Al)O10(OH)8 P 2₁/a 2/m

09.EC.55 Chamosite (Fe,Mg,Fe)5Al(Si3Al)O10(OH,O)8 C 2/m 2/m

09.EC.55 Franklinfurnaceite Ca2(Fe,Al)MnMn3Zn2Si2O10(OH)8 C 2 2

09.EC.55 Nimite (Ni,Mg,Fe)5Al(Si3Al)O10(OH)8 C 2/m 2/m

09.EC.55 Gonyerite Mn3[Mn3Fe][(Si,Fe)4O10](OH,O)8 pseudo-HEX Ortho

09.EC.55 Odinite (Fe,Mg,Al,Fe,Ti,Mn)2.5(Si,Al)2O5(OH)4 Cm m

09.EC.55 Orthochamosite (Fe,Mg,Fe)5Al(Si3Al)O10(OH,O)8 C3m-pseudoHEX Ortho

09.EC.55 Pennantite Mn5Al(Si3Al)O10(OH)8 C 2/m 2/m

09.EC.55 Sudoite Mg2(Al,Fe)3Si3AlO10(OH)8 C 2/m 2/m

09.EC.55 Glagolevite! NaMg6[Si3AlO10](OH,O)8•H2O C1 1

09.EC.55 Borocookeite! Li(13x)Al(4-x)(BSi3)O10(OH,F)8[x=0-0.33] pseudo C 2/m 2/m

Other Pennantite 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 Pennantite :
1 - Am. Min. Crystal Structure Database
2 - Athena
3 - EUROmin Project
4 - Ecole des Mines de Paris
5 - GeoScienceWorld
6 - Google Images
7 - Google Scholar
8 - Handbook of Mineralogy (MinSocAm)
9 - Handbook of Mineralogy (UofA)
10 - MinDAT
11 - Mineralienatlas (Deutsch)
12 - Online Mineral Museum
13 - QUT Mineral Atlas
14 - Ruff.Info

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Pennantite

Mn5Al(Si3Al)O10(OH)8
Dana No: 71.04.01.08 Strunz No: 09.EC.55
Locality:

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