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Tetraferriannite

You find additional specimen at the Geolitho Museum

Collectors Summary

Color braun, bräunlichschwarz
Streak color hellbraun
Lustre Diamantglanz, Glasglanz
Hardness (Mohs) 2.75
Crystal System monoklin, C2/m

Chemism

Chemical formula

KFe2+3(Si3Fe3+)O10(OH)2

Chemical composition

Eisen, Silicium, Kalium, Sauerstoff, Wasserstoff

Unit weight: 540.744754 u; Number of atoms in the formula: 22

Info

Empirical formula:

KFe3(Si3Fe)O10(OH)2

Element

Symbol

Weight%

Atoms

Atoms%

Atom weight (u)

Sum weight (u)
Hydrogen

H

0.37

2

9.09

1.0079470

2.0158940
Oxygen

O

35.51

12

54.55

15.9994300

191.9931600
Silicon

Si

15.58

3

13.64

28.0855300

84.2565900
Potassium

K

7.23

1

4.55

39.0983100

39.0983100
Iron

Fe

41.31

4

18.18

55.8452000

223.3808000

Analysis wt%

SiO2 : 36.23, Al2O3 : 1.83, Fe2O3 : 11.98, FeO : 29.57, MgO : 7.56, K2O : 7.87, H2O : 3.50 (Ref: American Mineralogist 82)

Strunz 9th edition incl. updates

9.EC.20

9: Silikate (Germanate)
E: Schichtsilikate (Phyllosilikate)
C: Schichtsilikate (Phyllosilikate) mit Glimmer Tafeln, zusammengesetzt aus tetrahedralen oder octahedralen Netzen
20:Phlogopit-Gruppe

Lapis Classification

VIII/H.11-120

VIII: SILIKATE
H: Schichtsilikate
11: Glimmerartige Schicht-silikate mit Baugruppen [Si4O10] 4- und verwandte Strukturen; Glimmer-Gruppe; Lithionit/Biotit-Reihe

Classification by Hölzel

9.ED.150

9: SILICATES
E: Phyllosilicates
D: Biotite-Group

Dana 8th edition

71.02.02b.04

71: Phyllosilicate Minerals
02: Phyllosilicates Phyllosilicate Sheets of Six-Membered Rings with 2:1 Layers
02b: Mica Group (Biotite subgroup)

IMA Classification

IMA Classification

 Mica group  ⇒ True micas

Optical Properties

Color

braun, bräunlichschwarz

Streak color

hellbraun

Diaphaneity (Transparency)

transparent, durchscheinend

Lustre

Diamantglanz, Glasglanz

max. Birefringence

0.038
Birefringence chart\! Tetraferriannite title=Birefringence chart Tetraferriannite

Michel-Levy Color Chart viewed according to the maximum birefringence (at 30μm). Mineral color is not taken into account. Click on the image to enlarge or change thickness.

RI value α / ω / n

1.653 - 1.677

RI value γ / ε

1.691 - 1.721

Ri mean

1.686

2V angle

Buaxial (-) 0° - 10° (gemessen)

Dispersion

schwach

Pleochroism

gelblich grün, bräunlich rot

Crystallography

Crystal System

monoklin

Class (H-M)

2/m

Space Group number

12

Space Group

C2/m

Cell parameters a (Å)

5.402

Cell parameters b (Å)

9.237

Cell parameters c (Å)

10.306

Cell parameters a/b or c/a

0.585

Cell parameters c/b

1.116

Cell parameters α

90°

Cell parameters β

99.27

Cell parameters γ

90°

Z

2

Volume (ų)

507.536

X-Ray Powder Diffraction

10.2(100),
3.684(50),
3.379(50),
2.905(10),
2.666(10),
1.696(50),
1.600(30),
1.539(10)
XRD chart Tetraferriannite

Calculated from d-spacing and intensity at 0.1541838 nm (Cu)

Crystal Structure 3D

Open larger view

Physical Properties

Hardness (Mohs)

2.75

VHN (Hardness Vickers)

68 (ungefähre Angabe abgeleitet aus der Mohshärte)

Density (g/cm³)

3.54 (berechnet)

3.538 ( ρ calc. Mineralienatlas )

(Co-)Type locality

(Co-)Type locality

Australien/Western Australia/Pilbara/Hamersley Ranges/Wittenoom Gorge/Colonial Asbestos Mine

Preface

Author (Name, Year)

Wones, 1963

References

American Journal of Science 261 (1963), 581

American Mineralogist 67 (1982), 1179

American Mineralogist 84 (1999), 325

Canadian Mineralogist 36 (1998),905

Acta Crystallographica C60 (2004), i33

Mineralogical Record 39 (2008), 131

IMA group assignments

Other languages

German

Tetraferriannit

Spanish

Tetraferriannita

English

Tetraferriannite

Russian

тетраферрианнит

Japanese

ﾃﾄﾗﾌｪﾘ鉄雲母

Alternative Name

Ferri-Annit

Ferri-annite

German

Tetra-Ferri-Annit

French

Tetra-Ferri-Annite

Tetra-ferri-annite

English

Tetra-ferri-annite

Russian

Феррианнит

CNMNC symbol

Symbol

Tfann

Locations with GPS information

IDs

GUSID (Global unique identifier short form) UconmZgaxUq7FAIokT8KRw
GUID (Global unique identifier) 9927CA51-1A98-4AC5-BB14-0228913F0A47
Database ID 3805