Ferripyrophyllite Mineral Data

General Ferripyrophyllite Information

Chemical Formula:

Fe+++2Si4O10(OH)2

Composition:

Molecular Weight = 418.04 gm

Iron 26.72 % Fe 38.20 % Fe₂O₃

Silicon 26.87 % Si 57.49 % SiO₂

Hydrogen 0.48 % H 4.31 % H₂O

Oxygen 45.93 % O

______ ______

100.00 % 100.00 % = TOTAL OXIDE

Empirical Formula:

Fe³⁺₂Si₄(OH)₂O₁₀

Environment:

Found on a museum specimen from the Strassenschacht hematite deposit.

IMA Status:

Approved IMA 1979

Locality:

Strassenschacht, Germany. Link to MinDat.org Location Data.

Name Origin:

Named as the Fe+++ analog of pyrophyllite.

Name Pronunciation:

Ferripyrophyllite + Pronunciation

Ferripyrophyllite Image

Images:

Ferripyrophyllite

Comments: Brown crystal prism of ferripyrophyllite in earthy matrix.
Location: Talagai, Kazakhstan. Scale: See Photo.
© Jeff Weissman / Photographic Guide to Mineral Species

Ferripyrophyllite Crystallography

Axial Ratios:

a:b:c =0.578:1:2.0989

Cell Dimensions:

a = 5.26, b = 9.1, c = 19.1, Z = 4; beta = 95.5° V = 910.03 Den(Calc)= 3.05

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): 4.54(1), 1.518(0.8), 9.6(0.8),

Physical Properties of Ferripyrophyllite

Cleavage:

{001} Perfect

Color:

Brownish yellow.

Density:

2.6 - 3, Average = 2.8

Diaphaneity:

Transparent to Translucent

Fracture:

Plastic - Deforms like soft, plastic materials.

Habit:

Scaly - Morphology like fish scales.

Hardness:

1.5-2 - Talc-Gypsum

Luster:

Pearly

Streak:

light yellow

Optical Properties of Ferripyrophyllite

Gladstone-Dale:

CI meas= 0.043 (Good) - where the CI = (1-KPDmeas/KC)
CI calc= 0.122 (Poor) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.2236,KPDmeas= 0.2436,KC= 0.2546
Ncalc = 1.66 - 1.78

Optical Data:

Biaxial (?), b=1.676-1.678, g=1.686-1.688,

Pleochroism (x):

greenish.

Pleochroism (y):

greenish.

Pleochroism (z):

bright yellow.

Calculated Properties of Ferripyrophyllite

Electron Density:

Bulk Density (Electron Density)=2.76 gm/cc
note: Specific Gravity of Ferripyrophyllite =2.80 gm/cc.

Fermion Index:

Fermion Index = 0.01
Boson Index = 0.99

Photoelectric:

PE_{Ferripyrophyllite}= 8.95 barns/electron
U=PE_{Ferripyrophyllite} x rElectron Density= 24.70 barns/cc.

Radioactivity:

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

Ferripyrophyllite Classification

Dana Class:

71.02.01.02 (71)Phyllosilicate Sheets of Six-Membered Rings

(71.02)with 2:1 Layers

(71.02.01)Pyrophyllite-talc group

71.02.01.01 Pyrophyllite Al2Si4O10(OH)2 P1 1

71.02.01.02 Ferripyrophyllite Fe2Si4O10(OH)2 C 2/m 2/m

71.02.01.03 Talc Mg3Si4O10(OH)2 C 2/c 2/m

71.02.01.04 Willemseite (Ni,Mg)3Si4O10(OH)2 C 2/c 2/m

71.02.01.05 Minnesotaite (Fe,Mg)3Si4O10(OH)2 C1 1

71.02.01.06 Brinrobertsite! (Na,K,Ca)x(Al,Fe,Mg)4(Si,Al)8O20(OH)4•3.54(H2O)[x=0.35,n=3.54] pseudo 2/m 2/m

Strunz Class:

09.EC.10 09 - SILICATES (Germanates)

09.E - Phyllosilicates

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

09.EC.10 Ferripyrophyllite Fe2Si4O10(OH)2 C 2/m 2/m

09.EC.10 Pyrophyllite Al2Si4O10(OH)2 P1 1

Other Ferripyrophyllite Information

References:

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

See Also:

Links to other databases for Ferripyrophyllite :
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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Ferripyrophyllite

Fe+++2Si4O10(OH)2
Dana No: 71.02.01.02 Strunz No: 09.EC.10
Locality:

Notes:

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