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Townendite

Collectors Summary

Hardness (Mohs) 5.5
Crystal System trigonal, R3m

Chemism

Chemical formula

Na8ZrSi6O18

Additional chem. information

Lovozerit-Gruppe

Chemical composition

Natrium, Silicium, Zirconium, Sauerstoff

Unit weight: 731.6452816 u; Number of atoms in the formula: 33

Info

Empirical formula:

Na8ZrSi6O18

Element

Symbol

Weight%

Atoms

Atoms%

Atom weight (u)

Sum weight (u)

Oxygen

O

39.36

18

54.55

15.9994300

287.9897400

Sodium

Na

25.14

8

24.24

22.9897702

183.9181616

Silicon

Si

23.03

6

18.18

28.0855300

168.5131800

Zirconium

Zr

12.47

1

3.03

91.2242000

91.2242000

Strunz 9th edition incl. updates

9.CJ.15

9: Silikate (Germanate)
C: Ringsilikate (Cyclosilikate)
J: ~[Si6O18]12- sechser-Einfachringe, ohne inselartig, komplexe [Anionen]
15:Lovozerit-Gruppe

Lapis Classification

VIII/E.16-035

VIII: SILIKATE
E: Ringsilikate
16: Sechserringe [Si6O18] 12-; Lovozerit-Gruppe

Classification by Hölzel

9.CD.110

9: SILICATES
C: Cyclosilicates
D: ~[Si6O18]-rings, without borate
1: Zirsinalite-Lovozerite-Subgroup - Cation-saturated members (with occupied B-site)

IMA status

anerkannt, IMA Web-Seite - Neue Mineralien Nov. 2009

Mineral status

anerkanntes Mineral

Optical Properties

max. Birefringence

0.008

Birefringence chart\! Townendite title=Birefringence chart Townendite

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

1.563

RI value γ / ε

1.555

Ri mean

1.560

2V angle

Uniaxial (-)

Crystallography

Crystal System

trigonal

Class (H-M)

3m

Space Group number

166

Space Group

R3m

Cell parameters a (Å)

10.345

Cell parameters b (Å)

-

Cell parameters c (Å)

13.103

Cell parameters a/b or c/a

1.267

Cell parameters c/b

-

Z

3

Volume (ų)

1214.402

Crystal structure

Struktur bestimmt, siehe I.E. Grey et al., 2010

X-Ray Powder Diffraction

5.286(33), 5.175(28), 4.240(14), 3.698(100), 3.280(42), 2.645(42), 2.585(45), 1.849(35)

XRD chart Townendite

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

Crystal Structure 3D

Open larger view

Physical Properties

Hardness (Mohs)

5.5

VHN (Hardness Vickers)

530 (ungefähre Angabe abgeleitet aus der Mohshärte)

Density (g/cm³)

2.89 (berechnet)

3.001 ( ρ calc. Mineralienatlas )

Preface

Author (Name, Year)

Ian E. Grey et al., 2010

References

Ian E. Grey, Colin M. Macrae, W. Gus Mumme, and Allan Pring: Townendite, Na8ZrSi6O18, a new uranium-bearing lovozerite group mineral from the Ilímaussaq alkaline complex, Southern Greenland. American Mineralogist 95 (2010) S.646-650.

Neue Mineralien - IMA Web-Seite November 2009

Macrae, C.M., Torpy, A., Wilson, N., Grey, I., Townend, R. (2009): The discovery and characterisation of a new U mineral from Ilímaussaq Alkali Complex – Greenland. Microscopy and Microanalysis, 15 (Suppl. 2), 522-523.

Other languages

German

Townendit

Spanish

Townendita

English

Townendite

CNMNC (IMA)-Number

IMA 2009-066

CNMNC symbol

Symbol

Twn

Locations with GPS information

IDs

GUSID (Global unique identifier short form) jFaEm5mJXkuziyvNdODw3w
GUID (Global unique identifier) 9B84568C-8999-4B5E-B38B-2BCD74E0F0DF
Database ID 5300