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Cummingtonite (Magnesiocummingtonit)

Pictures (3 Images total)

Cummingtonit
Views (File:
1216633219
): 4642
Cummingtonit
FO: Gefunden in der Dannemora Mine, Uppsala Län, Uppland, Schweden, faserige, bräunliche Kristalle, Bildbreite 2,2 mm.
Copyright: Hannes Osterhammer; Contribution: Münchener Micromounter
Collection: Lithothek der Münchener Micromounter, Collection number: B000905, Donator: Manfred Seitz
Location: Schweden/Uppsala, Provinz/Östhammar/Dannemora/Dannemora Mine
Mineral: Cummingtonite
Image: 1216633219
Rating: 8.5 (votes: 2)
License: Usage for Mineralienatlas project only
Cummingtonit (SNr: B000905)

FO: Gefunden in der Dannemora Mine, Uppsala Län, Uppland, Schweden, faserige, bräunliche Kristalle, Bildbreite 2,2 mm.
Collection: Lithothek der Münchener Micromounter
Copyright: Hannes Osterhammer
Contribution: Münchener Micromounter 2008-07-21
Locality: Dannemora Mine / Dannemora / Östhammar / Uppsala, Provinz / Schweden
Cummingtonit
Views (File:
1292446001
): 3835
Cummingtonit
Bräunliche strahlige Kristallaggregate; BB = 9,2 mm. Fundort: Te Aroha Station, Hokitika, West Coast Region, South Island, Neuseeland.
Copyright: Hannes Osterhammer; Contribution: Münchener Micromounter
Collection: Lithothek der Münchener Micromounter, Collection number: A009216, Donator: Ron Keene
Location: Neuseeland/South Island/West Coast, Region/Hokitika/Te Aroha Station
Mineral: Cummingtonite
Image: 1292446001
License: Usage for Mineralienatlas project only
Cummingtonit (SNr: A009216)

Bräunliche strahlige Kristallaggregate; BB = 9,2 mm. Fundort: Te Aroha Station, Hokitika, West Coast Region, South Island, Neuseeland.
Collection: Lithothek der Münchener Micromounter
Copyright: Hannes Osterhammer
Contribution: Münchener Micromounter 2010-12-15
Locality: Te Aroha Station / Hokitika / West Coast, Region / South Island / Neuseeland
Cummingtonit
Views (File:
1613639864
): 604
Cummingtonit
Södra, Garpenberg, Hedemora, Dalarna, SE. BB: 5cm.
Copyright: Doc Diether; Contribution: Doc Diether
Collection: Doc Diether
Location: Schweden/Dalarna, Provinz/Hedemora/Garpenberg/Södra
Mineral: Cummingtonite
Image: 1613639864
License: Usage for Mineralienatlas project only
Cummingtonit

Södra, Garpenberg, Hedemora, Dalarna, SE. BB: 5cm.
Collection: Doc Diether
Copyright: Doc Diether
Contribution: Doc Diether 2021-02-18
Locality: Södra / Garpenberg / Hedemora / Dalarna, Provinz / Schweden

You find additional Magnesiocummingtonit specimen at the Geolitho Museum

Collectors Summary

Color dunkelgrün
Streak color weiß
Hardness (Mohs) 5.00 - 6.00
Solubility +++ HF, - HCl
Crystal System monoklin, C2/m

Chemism

Chemical formula

☐(Mg,Fe2+,Mn2+)7Si8O22(OH)2

Chemical composition

Eisen, Magnesium, Mangan, Silicium, Sauerstoff, Wasserstoff, Vakanz

Unit weight: 868.49926094 u; Number of atoms in the formula: 42

Info

Empirical formula:

Vc(Mg0.6Fe0.3Mn0.1)7Si8O22(OH)2

Element

Symbol

Weight%

Atoms

Atoms%

Atom weight (u)

Sum weight (u)
Vacancy

Vc

0.00

1

2.38

0.0000000

0.0000000
Hydrogen

H

0.23

2

4.76

1.0079470

2.0158940
Oxygen

O

44.21

24

57.14

15.9994300

383.9863200
Magnesium

Mg

11.75

4.2

10.00

24.3050600

102.0812520
Silicon

Si

25.87

8

19.05

28.0855300

224.6842400
Manganese

Mn

4.43

0.7

1.67

54.9380499

38.4566349
Iron

Fe

13.50

2.1

5.00

55.8452000

117.2749200

Analysis wt%

SiO2 : 52.28, FeO : 31.90, MnO : 0.57, MgO : 12.35, CaO : 0.79, H2O : 1.62 (Ref: American Mineralogist 64)

Strunz 9th edition incl. updates

9.DE.05

9: Silikate (Germanate)
D: Ketten- und Bandsilikate (Inosilikate)
E: Ketten- und Bandsilikate mit 2-periodischen Doppelketten, Si4O11; Amphibol-Familie, Klinoamphibole
05:Anthophyllit (Ath) Amphibole

Lapis Classification

VIII/F.07-020

VIII: SILIKATE
F: Ketten- und Bandsilikate
7: Zweierbänder [Si4O11] 6-; Amphibol-Gruppe; Mg-Fe-Mn-Amphibole

Classification by Hölzel

9.DG.100

9: SILICATES
D: Inosilicates; ~[Si2O6]4--...2-Chain
G: Amphiboles; Monoclinic Amphiboles
1: Cummingtonite-Grünerite-Group

Dana 8th edition

66.01.01.02

66: Inosilicates Inosilicate Double-Width Unbranched Chains, W=2
01: Inosilicates Inosilicate Double-Width Unbranched Chains, W=2 with P=2 amphibole configuration
01: Group 1, the Mg-Fe-Mn-Li amphiboles (Monoclinic)

IMA status

Neudefinition von der CNMNC anerkannt

Mineral status

anerkanntes Mineral

IMA Classification

IMA Classification

 Amphibole supergroup  ⇒ (OH,F,Cl)-dominant amphiboles  ⇒ Magnesium-iron-manganese amphiboles  ⇒ Cummingtonite (Cum) amphiboles

Optical Properties

Color

dunkelgrün

Streak color

weiß

max. Birefringence

0.032
Birefringence chart\! Cummingtonite title=Birefringence chart Cummingtonite

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

1.656

RI value β

1.671

RI value γ / ε

1.688

Ri mean

1.672

2V angle

Biaxial (+) 87°!

Optical Data Luminescence

Color LW-UV (365nm)

  

gelblich weiß

Afterglow (Persistant Luminescence)

keine Daten

Crystallography

Crystal System

monoklin

Class (H-M)

2/m

Space Group number

12

Space Group

C2/m

Cell parameters a (Å)

9.534

Cell parameters b (Å)

18.321

Cell parameters c (Å)

5.324

Cell parameters a/b or c/a

0.520

Cell parameters c/b

0.291

Cell parameters α

90°

Cell parameters β

101.97

Cell parameters γ

90°

Z

2

Volumne (ų)

909.735

X-Ray Powder Diffraction

9.16(40),
8.32(100),
4.58(10),
3.270(20),
3.072(20),
2.763(20),
2.635(30),
1.599(10)
XRD chart Cummingtonite

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

Crystals 3D

Open larger view

Crystal Structure 3D

Open larger view

Physical Properties

Hardness (Mohs)

5.00 - 6.00

VHN (Hardness Vickers)

530 (ungefähre Angabe abgeleitet aus der Mohshärte)

Density (g/cm³)

3.37 (gemessen)

3.17 ( ρ calc. Mineralienatlas )

Instability

+++ HF, - HCl

(Co-)Type locality

(Co-)Type locality

USA/Massachusetts/Hampshire Co./Cummington

Preface

Author (Name, Year)

Dewey, 1824

References

Canadian Mineralogist 35 (1997), 219

IMA group assignments

 
Amphibole supergroup
 
 
 

 
 
(OH,F,Cl)-dominant amphiboles
 
 
 

 
 
 
Magnesium-iron-manganese amphiboles
 
 
 

 
 
 
 
Cummingtonite (Cum) amphiboles
 
 
 

 
 
 
 
 
Cummingtonite
☐(Mg,Fe2+,Mn2+)7Si8O22(OH)2
monoklin
C2/m

 
 
 
 
 
Manganocummingtonite
☐Mn2(Mg,Fe)5Si8O22(OH)2
monoklin
C2/m

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Actuality: 24. Mar 2023 - 02:18:13

Other languages

Dutch

Cummingtoniet

German

Cummingtonit

Spanish

Cummingtonita

English

Cummingtonite

French

Cummingtonite

Russian

Куммингтонит

Ukrainian

Кумінгтоніт

Japanese

ｶﾐﾝﾄﾝ閃石

Alternative Name

Amphibole-anthophyllite

German

Antholit

Spanish

Antholita

English

Clino-anthophyllite

German

Kievit

Spanish

Kievita

English

Kievite

Magnesiocummingtonit

Spanish

Magnesiocummingtonita

Magnesiocummingtonite

Simplified Chinese

铁镁闪石

Simplified Chinese

镁铁闪石

CNMNC symbol

Symbol

Cum

Locations with GPS information