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Rankamaite

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Rankamait
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Rankamait
Bildbreite: 5 mm, Fundort: Masisi, Mumba, Provinz Nord-Kivu, Demokratische Republik Kongo
Copyright: Leonardus; Contribution: thdun5
Location: Demokratische Republik Kongo/Nord-Kivu, Provinz/Masisi-Gebiet
Mineral: Rankamaite
Image: 1360546427
Rating: 6 (votes: 1)
License: Usage for Mineralienatlas project only
Rankamait

Bildbreite: 5 mm, Fundort: Masisi, Mumba, Provinz Nord-Kivu, Demokratische Republik Kongo

Copyright: Leonardus
Contribution: thdun5 2013-02-11
Locality: Masisi-Gebiet / Nord-Kivu, Provinz / Demokratische Republik Kongo

Collectors Summary

Color cremeweiß
Streak color weiß
Lustre Seidenglanz
Hardness (Mohs) 3.00 - 4.00
Crystal System orthorhombisch, C222

Chemism

Chem­ical formula

(Na,K)3(Ta,Nb,Al)11(O,OH)31

Empir­ical formula (anal­y­sis)

(Na1.55K1.28)(Ta8.45Nb1.64Al0.89Fe3+0.01Ti0.01)[O25.02(OH)5.98]

Chem­ical com­po­si­tion

Aluminium, Natrium, Niob, Tantal, Kalium, Sauerstoff, Wasserstoff

Unit weight: 2294.116831648 u; Number of atoms in the formula: 50.81

Info

Empirical formula:

(Na1.55K1.28)(Ta8.45Nb1.64Al0.89Fe0.01Ti0.01)[O25.02(OH)5.98]

Element

Symbol

Weight%

Atoms

Atoms%

Atom weight (u)

Sum weight (u)

Hydrogen

H

0.26

5.98

11.77

1.0079470

6.0275231

Oxygen

O

21.62

31

61.01

15.9994300

495.9823300

Sodium

Na

1.55

1.55

3.05

22.9897702

35.6341438

Aluminium

Al

1.05

0.89

1.75

26.9815382

24.0135690

Potassium

K

2.18

1.28

2.52

39.0983100

50.0458368

Titanium

Ti

0.02

0.01

0.02

47.8671000

0.4786710

Iron

Fe

0.02

0.01

0.02

55.8452000

0.5584520

Niobium

Nb

6.64

1.64

3.23

92.9063820

152.3664665

Tantalum

Ta

66.65

8.45

16.63

180.9479100

1,529.0098395

Anal­y­sis wt%

Ta2O5 : 69.47, Nb2O5 : 17.40, Al2O3 : 3.40, PbO : 2.63, Na2O : 2.31, K2O : 1.80, SiO2 : 0.96, H2O : 1.90 (Ref: BGSF69)

Strunz 9th edi­tion incl. updates

4.DM.05

4: Oxide, Hydroxide (Oxide, Hydroxide, V[5,6]-Vanadate, Arsenite, Antimonite, Bismutite, Sulfite, Selenite, Tellurite, Iodate)
D: Metall: Sauerstoff = 1:2 und vergleichbare
M: Mit großen (± mittelgroßen) [Kationen]; unklassifiziert
05:Rankamait-Gruppe

Lapis Clas­sifica­tion

IV/D.27-040

IV: OXIDE
D: Oxide mit Verhältnis Metall : Sauerstoff = 1:2 (MO2 und verwandte Verbindungen)

Clas­sifica­tion by Hölzel

4.DK.320

4: OXIDES
D: Dioxides
K: Other Niobates, Tantalates
3: Natrotantite-Group

Dana 8th edi­tion

08.07.06.01

08: Multiple Oxides with Nb, Ta, and Ti
07: Multiple Oxides with Nb, Ta, and Ti

IMA sta­tus

Anerkannt von der CNMNC

Min­eral sta­tus

anerkanntes Mineral

Optical Properties

Color

cremeweiß

Streak color

weiß

Diaphane­ity (Trans­parency)

Semitransparent

Lus­tre

Seidenglanz

RI value α / ω / n

> 2.1

RI value β

> 2.1

RI value γ / ε

> 2.1

2V angle

Biaxial

Ori­enta­tion

Z = c

Crystallography

Crystal Sys­tem

orthorhombisch

Class (H-M)

222

Space Group number

21

Space Group

C222

Cell param­e­ters a (Å)

17.224

Cell param­e­ters b (Å)

17.687

Cell param­e­ters c (Å)

3.9361

Cell param­e­ters a/b or c/a

0.974

Cell param­e­ters c/b

0.223

Cell param­e­ters α

90°

Cell param­e­ters β

90°

Cell param­e­ters γ

90°

Z

2

Volumne (ų)

1199.097

X-Ray Pow­der Diffrac­tion

4.112(30),
3.935(40),
3.467(50),
3.375(60),
3.011(80),
2.970(100),
2.791(30),
1.736(30)

XRD chart Rankamaite

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

Crystal Structure 3D

Open larger view

Physical Properties

Hard­ness (Mohs)

3.00 - 4.00

VHN (Hard­ness Vick­ers)

130 (ungefähre Angabe abgeleitet aus der Mohshärte)

Density (g/cm³)

6.2 (berechnet) 5.5 (gemessen)

6.354 ( ρ calc. Mineralienatlas )

Preface

Name from

Professor Kalervo Rankama (1913–1995), finnischer Geochemiker, Universität von Helsinki, Helsinki, Finnland

Author (Name, Year)

von Knorring & Vorma & Nixon, 1969

References

Bulletin de la Société Française Minéralogie et de Cristallographie 104 (1981), 496

American Mineralogist, Volume 96, pages 1455–1460, 2011 [Kristalldaten, Formel]

Other languages

German

Rankamait

English

Rankamaite

French

Rankamaite

Spanish

Rankamaíta

Russian

Ранкамаит

CNMNC (IMA)-Number

IMA 1968-002

CNMNC symbol

Symbol

Rkm

Automatic Links to external internet sources (Responsibility is with the operator)

German pages

DeWikiPedia - search for: Rankamait
Google-Bilder-Suche - search for: Rankamait
Mineralienatlas.de (Forum) - search for: Rankamait

English pages

Mindat - search for: Rankamaite
Webmineral - search for:Rankamaite
Handbook-of-Mineralogy - search for: Rankamaite
RRUFF - Raman, XRD and other mineral data - search for: Rankamaite
RRUFF - References and PDF downloads - search for: Rankamaite
American-Mineralogist-Crystal-Structure-Database - search for: Rankamaite
Strahlen.org - search for: Rankamaite

Russian pages

Webmineral.ru - search for: Ранкамаит

Mineral Dealer

German pages

hausen - Mineralgroßhandel - search for: Rankamait
Crystal-Treasure.com - search for: Rankamait
Bosse - search for: Rankamait
Edelsteine Neuburg - Gundolf Fischer - search for: Rankamait

Locations with GPS information