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Walthierite (Walthierit)

Collectors Summary

Color weiß, gelblich
Streak color weiß
Cleavages vollkommen {001}
Fracture nicht genannt
Crystal System trigonal, R3m

Chemism

Chemical formula

Ba0.5Al3(SO4)2(OH)6

Chemical composition

Aluminium, Barium, Sauerstoff, Schwefel, Wasserstoff

Unit weight: 443.7791666 u; Number of atoms in the formula: 25.5

Info

Empirical formula:

Ba0.5Al3(SO4)2(OH)6

Element

Symbol

Weight%

Atoms

Atoms%

Atom weight (u)

Sum weight (u)
Hydrogen

H

1.36

6

23.53

1.0079470

6.0476820
Oxygen

O

50.47

14

54.90

15.9994300

223.9920200
Aluminium

Al

18.24

3

11.76

26.9815382

80.9446146
Sulfur

S

14.45

2

7.84

32.0655000

64.1310000
Barium

Ba

15.47

0.5

1.96

137.3277000

68.6638500

Analysis wt%

K2O : 0.42, BaO : 16.17, Al2O3 : 33.65, SO3 : 34.59, H2O : 11.89 (Ref: American Mineralogist 92)

Strunz 9th edition incl. updates

7.BC.10

7: Sulfate (Selenate, Tellurate, Chromate, Molybdate, Wolframate)
B: Sulfate (Selenate, etc.) mit weitere Anionen, ohne H2O
C: Mit mittelgroßen und großen [Kationen]
10:Alunit-Gruppe

Lapis Classification

VI/B.11-045

VI: SULFATE, CHROMATE, MOLYBDATE UND WOLFRAMATE
B: Wasserfreie Sulfate, mit fremden Anionen
11: Große Kationen vorwiegend; Alunit-Gruppe

Classification by Hölzel

7.BB.530

7: SULFATES CHROMATES MOLYBDATES WOLFRAMATES
B: Sulfates (+Anions -Water)
B: Alunite-Group (sulfatian)
5: Alunites-2R

Dana 8th edition

30.02.04.07

30: Anhydrous Sulfates Containing Hydroxyl or Halogen
02: Anhydrous Sulfates Containing Hydroxyl or Halogen where (A B)2 XO4 Zq
04: Alunite Group (Alunite Subgroup)

IMA status

Anerkannt von der CNMNC

Mineral status

anerkanntes Mineral

IMA Classification

IMA Classification

 Alunite supergroup  ⇒ Alunite group with -2c

Optical Properties

Color

weiß, gelblich

Streak color

weiß

Diaphaneity (Transparency)

transparent

max. Birefringence

0.016
Birefringence chart\! Walthierite title=Birefringence chart Walthierite

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

1.588

RI value γ / ε

1.604

Ri mean

1.593

2V angle

Uniaxial (+)

Crystallography

Crystal System

trigonal

Class (H-M)

3m

Space Group number

166

Space Group

R3m

Cell parameters a (Å)

6.992

Cell parameters b (Å)

-

Cell parameters c (Å)

34.443

Cell parameters a/b or c/a

4.926

Cell parameters c/b

-

Z

6

Volumne (ų)

1458.258

X-Ray Powder Diffraction

5.73(50),
4.97(40),
3.49(50),
2.98(100),
2.283(80),
1.909(70),
1.747(60),
1.503(40)
XRD chart Walthierite

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

Crystals 3D

Open larger view

Physical Properties

Density (g/cm³)

3.02 (berechnet)

3.032 ( ρ calc. Mineralienatlas )

Cleavages

vollkommen {001}

Fracture

nicht genannt

(Co-)Type locality

(Co-)Type locality

Chile/Coquimbo, Region (IV. Region)/Limari, Provinz/Ovalle/El Indio/Tambo Mine/Retna

Preface

Author (Name, Year)

Li & Peacor & Essene & Brosnahan & Beane, 1992

References

American Mineralogist 77 (1992), 1275.

Canadian Mineralogist 37 (1999), 1323.

IMA group assignments

Other languages

German

Walthierit

Spanish

Walthierita

French

Walthierite

English

Walthierite

CNMNC (IMA)-Number

IMA 1991-008

CNMNC symbol

Symbol

Wtr

Locations with GPS information