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Johnwalkite

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Johnwalkit
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Johnwalkit
braunes Aggregat von Johnwalkit, Champion Mine, Keystone, Pennington Co., South Dakota, USA; BB ~ 1 mm, analysiert
Copyright: MinTreasure.com (Carsten Slotta); Contribution: openpit
Location: USA/South Dakota/Pennington County/Keystone District/Keystone/Champion Mine
Mineral: Johnwalkite
Image: 1633547751
License: Usage for Mineralienatlas project only
Johnwalkit

braunes Aggregat von Johnwalkit, Champion Mine, Keystone, Pennington Co., South Dakota, USA; BB 1 mm, analysiert
Copyright: MinTreasure.com (Carsten Slotta)
Contribution: openpit 2021-10-06
Locality: Champion Mine / Keystone / Keystone District / Pennington County / South Dakota / USA

Collectors Summary

Hardness (Mohs) 4
Crystal System orthorhombisch, Pb21m

Chemism

Chemical formula

K(Mn2+,Fe3+,Fe2+)2(Nb,Ta)(PO4)2O2(H2O,OH)2

Chemical composition

Eisen, Mangan, Niob, Tantal, Kalium, Phosphor, Sauerstoff, Wasserstoff

Unit weight: 522.08539078 u; Number of atoms in the formula: 21.5

Info

Empirical formula:

K(Mn0.6Fe0.3Fe0.1)2(Nb0.75Ta0.25)(PO4)2O2((H2O)0.75(OH)0.25)2

Element

Symbol

Weight%

Atoms

Atoms%

Atom weight (u)

Sum weight (u)
Hydrogen

H

0.68

3.5

16.28

1.0079470

3.5278145
Oxygen

O

36.77

12

55.81

15.9994300

191.9931600
Phosphorus

P

11.87

2

9.30

30.9737612

61.9475224
Potassium

K

7.49

1

4.65

39.0983100

39.0983100
Manganese

Mn

12.63

1.2

5.58

54.9380499

65.9256599
Iron

Fe

8.56

0.8

3.72

55.8452000

44.6761600
Niobium

Nb

13.35

0.75

3.49

92.9063820

69.6797865
Tantalum

Ta

8.66

0.25

1.16

180.9479100

45.2369775

Analysis wt%

Fe2O3 : 12.50, FeO : 3.30, MgO : 0.50, MnO : 14.80, K2O : 8.60, Ta2O5 : 5.10, Nb2O5 : 21.50, P2O5 : 27.30, H2O : 6.50 (Ref: Neues Jahrbuch für Mineralogie, (Monatshefte) 86)

Strunz 9th edition incl. updates

8.DJ.05

8: Phosphate, Arsenate, Vanadate
D: Phosphate, mit weiteren Anionen, mit H2O
J: Mit großen und mittelgroßen [Kationen], (OH, etc.):RO4 = 1:1
05:Olmsteadit-Gruppe

Lapis Classification

VII/D.39-020

VII: PHOSPHATE, ARSENATE UND VANADATE ("Phosphate" des Registers immer einschließlich isotyper Arsenate und Vanadate!)
D: Wasserhaltige Phosphate, mit fremden Anionen
39: Mittelgroße und sehr große Kationen: Al-Mg und Ca-Na-K

Classification by Hölzel

8.DI.410

8: PHOSPHATES ARSENATES VANADATES
D: Phosphates (+Anions +Water)
I: C large, V=1(2) - C small-medium, V=2,3,4
4: With other Anions

Dana 8th edition

42.07.11.02

42: Hydrated Phosphates, etc., Containing Hydroxyl or Halogen
07: Hydrated Phosphates, etc., Containing Hydroxyl or Halogen where (AB)5 (XO4)3 Zq · x(H2O)
11: Olmsteadite Group

IMA status

Anerkannt von der CNMNC

Mineral status

anerkanntes Mineral

Optical Properties

max. Birefringence

0.09~
Birefringence chart\! Johnwalkite title=Birefringence chart Johnwalkite

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

1.748

RI value β

1.763

RI value γ / ε

1.84

Ri mean

1.784

2V angle

Biaxial (+) 53°

Crystallography

Crystal System

orthorhombisch

Class (H-M)

mm2

Space Group number

26

Space Group

Pb21m

Cell parameters a (Å)

7.516

Cell parameters b (Å)

10.023

Cell parameters c (Å)

6.502

Cell parameters a/b or c/a

0.750

Cell parameters c/b

0.649

Cell parameters α

90°

Cell parameters β

90°

Cell parameters γ

90°

Z

2

Volume (ų)

489.814

X-Ray Powder Diffraction

7.54(30),
6.51(40),
6.01(100),
3.256(30),
3.054(70),
3.005(80),
2.862(70),
2.563(40)
XRD chart Johnwalkite

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

Crystals 3D

Open larger view

Physical Properties

Hardness (Mohs)

4

VHN (Hardness Vickers)

190 (ungefähre Angabe abgeleitet aus der Mohshärte)

Density (g/cm³)

3.40 (gemessen)

3.54 ( ρ calc. Mineralienatlas )

(Co-)Type locality

(Co-)Type locality

USA/South Dakota/Pennington County/Keystone District/Keystone/Champion Mine

Preface

Author (Name, Year)

Dunn & Peacor & Sturman & Ramik & Roberts & Nelen, 1986

References

Neues Jahrbuch für Mineralogie, Monatshefte (1986), 115

Other languages

German

Johnwalkit

Spanish

Johnwalkita

English

Johnwalkite

French

Johnwalkite

Russian

Джонуолкит

CNMNC (IMA)-Number

IMA 1985-008

CNMNC symbol

Symbol

Jwk

IDs

GUSID (Global unique identifier short form) Io6FE9q5iESqHHzD_ZNncw
GUID (Global unique identifier) 13858E22-B9DA-4488-AA1C-7CC3FD936773
Database ID 1808