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Rankamaite

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Mumba, Masisi Mts, Nord-Kivu, Democratic Republic of Congo (Zaïre)
© Thomas Witzke

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Formula:
(Na,K)
 
3
(Ta,Nb,Al)
 
11
(O,OH)
 
31
System:OrthorhombicColour:Creamy-white
Hardness:3 - 4
Name:
Named after Professor Kalervo Rankama (1913–1995), Finnish geochemist, University of Helsinki, Helsinki, Finland.
This page provides mineralogical data about Rankamaite.

Classification of Rankamaite

IMA status:Approved
Strunz 8th edition ID:4/D.27-40
Nickel-Strunz 10th (pending) edition ID:4.DM.05

4 : OXIDES (Hydroxides, V[5,6] vanadates, arsenites, antimonites, bismuthites, sulfites, selenites, tellurites, iodates)
D : Metal: Oxygen = 1:2 and similar
M : With large (+- medium-sized) cations; unclassified
Dana 8th edition ID:8.7.6.1

8 : MULTIPLE OXIDES CONTAINING NIOBIUM,TANTALUM OR TITANIUM
7 : Miscellaneous
Hey's CIM Ref.:18.1.7

18 : Niobates and Tantalates
1 : Niobates and tantalates containing neither rare earths nor U
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Type Occurrence of Rankamaite

Type Locality:Mumba cassiterite gravels, Mumba, Masisi Mts, Nord-Kivu, Democratic Republic of Congo (Zaïre)
Year of Discovery:1969

Physical Properties of Rankamaite

Colour:Creamy-white
Hardness (Mohs):3 - 4

Crystallography of Rankamaite

Crystal System:Orthorhombic
Class (H-M):mmm (2/m 2/m 2/m) - Dipyramidal
Space Group:Cmmm {C2/m 2/m 2/m}
Space Group Setting:Cmmm
Cell Parameters:a = 17.224(3) Å, b = 17.687(3) Å, c = 3.9361(7) Å
α = 90°, β = 90°, γ = 90°
Ratio:a:b:c = 0.974 : 1 : 0.223
Unit Cell Volume:V 1199.1 ų
Z:2
Comment:Atencio et al. (2011)

Optical Data of Rankamaite

Type:Biaxial
Dispersion:r < v extreme

Chemical Properties of Rankamaite

Formula:
(Na,K)
 
3
(Ta,Nb,Al)
 
11
(O,OH)
 
31
Essential elements:Na, O, Ta
All elements listed in formula:Al, H, K, Na, Nb, O, Ta

Relationship of Rankamaite to other Species

Related Minerals - Nickel-Strunz Grouping):

- +
4.DM.05Sosedkoite
(K,Na)
 
5
Al
 
2
(Ta,Nb)
 
22
O
 
60
4.DM.15Cesplumtantite
(Cs,Na)
 
2
(Pb,Sb
3+
 
)
 
3
Ta
 
8
O
 
24
4.DM.20Eyselite
Fe
3+
 
Ge
4+
3
O
 
7
(OH)
4.DM.25Kuranakhite
PbMn
4+
 
Te
6+
 
O
 
6
Related Minerals - Hey's Index Grouping:

- +
18.1.1Lithiotantite
Li(Ta,Nb)
 
3
O
 
8
18.1.2Lueshite
NaNbO
 
3
18.1.3Natroniobite
NaNbO
 
3
18.1.4Franconite
Na
 
2
Nb
 
4
O
 
11
 · 9H
 
2
O
18.1.5Natrotantite
Na
 
2
Ta
 
4
O
 
11
18.1.6Irtyshite
Na
 
2
(Ta,Nb)
 
4
O
 
11
18.1.8Hydropyrochlore
(H
 
2
O,□)
 
2
Nb
 
2
(O,OH)
 
6
(H
 
2
O)
18.1.9Calciotantite
CaTa
 
4
O
 
11
18.1.10Rynersonite
Ca(Ta,Nb)
 
2
O
 
6
18.1.11Microlite Group
18.1.12Belyankinite
Ca
 
1-2
(Ti,Nb)
 
5
O
 
12
 · 9H
 
2
O (?)
18.1.13Latrappite
(Ca,Na)(Nb,Ti,Fe)O
 
3
18.1.14Hochelagaite
(Ca,Na,Sr)(Nb,Ti,Si,Al)
 
4
O
 
11
 · 8H
 
2
O
18.1.15Bariomicrolite (of Hogarth 1977)
18.1.16Parabariomicrolite
BaTa
 
4
O
 
10
(OH)
 
2
 · 2H
 
2
O
18.1.17Bariopyrochlore (of Hogarth 1977)
18.1.18Alumotantite
AlTaO
 
4
18.1.19Simpsonite
Al
 
4
(Ta,Nb)
 
3
O
 
13
(OH,F)
18.1.20Sosedkoite
(K,Na)
 
5
Al
 
2
(Ta,Nb)
 
22
O
 
60
18.1.21Thoreaulite
SnTa
 
2
O
 
6
18.1.22Stannomicrolite (of Hogarth 1977)
18.1.23Foordite
(Sn,Pb)(Nb,Ta)
 
2
O
 
6
18.1.24Changbaiite
PbNb
 
2
O
 
6
18.1.25Plumbopyrochlore (of Skorobogatova et al)
18.1.26Plumbomicrolite (of Hogarth 1977)
18.1.27Stibiocolumbite
Sb(Nb,Ta)O
 
4
18.1.28Stibiotantalite
Sb(Ta,Nb)O
 
4
18.1.29Natrobistantite
18.1.30Cesplumtantite
(Cs,Na)
 
2
(Pb,Sb
3+
 
)
 
3
Ta
 
8
O
 
24
18.1.31Stibiomicrolite (of Groat et al.)
18.1.32Cesstibtantite
18.1.34Bismutotantalite
Bi(Ta,Nb)O
 
4
18.1.35Bismutomicrolite (of Hogarth 1977)
18.1.36Tantalite-(Mn)
MnTa
 
2
O
 
6
18.1.37Gerasimovskite
(Mn,Ca)(Nb,Ti)
 
5
O
 
12
 · 9H
 
2
O
18.1.38Tapiolite-(Mn)
(Mn,Fe)(Ta,Nb)
 
2
O
 
6
18.1.39Columbite-(Mn)
(Mn,Fe)(Nb,Ta)
 
2
O
 
6
18.1.40Wodginite
Mn(Sn,Ta)Ta
 
2
O
 
8
18.1.41Ixiolite
(Ta,Nb,Sn,Fe,Mn)
 
4
O
 
8
18.1.42Columbite-(Fe)
FeNb
 
2
O
 
6
18.1.43Tantalite-(Fe)
FeTa
 
2
O
 
6
18.1.44Columbite
(Fe,Mn)(Nb,Ta)
 
2
O
 
6
18.1.45Tantalite
(Fe,Mn)(Ta,Nb)
 
2
O
 
6
18.1.46Tapiolite
(Fe,Mn)(Ta,Nb)
 
2
O
 
6
18.1.47Tapiolite-(Fe)
(Fe,Mn)(Ta,Nb)
 
2
O
 
6
18.1.48Columbite-(Mg)
(Mg,Fe,Mn)(Nb,Ta)
 
2
O
 
6
18.1.50Strüverite
(Ti,Ta,Fe)O
 
2
18.1.51 Staringite
(Fe,Mn)
 
x
(Ta,Nb)
 
2x
Sn
 
6-3x
O
 
12

Other Names for Rankamaite

Synonyms:
IMA1968-002
Other Languages:
German:Rankamait
Spanish:Rankamaita

Other Information

Health Warning:No information on health risks for this material has been entered into the database. You should always treat mineral specimens with care.

References for Rankamaite

Reference List:

- +
American Mineralogist (1970): 55: 1814.

Mineralogicheskii Zhurnal (1984): 6: 42-55.

Daniel Atencio, Reynaldo R. Contreira Fo., Stuart J. Mills, Jose M.V. Coutinho, Sara B. Honorato, Alejandro P. Ayala, Javier Ellena, and Marcelo B. de Andrade (2011) Rankamaite from the Urubu pegmatite, Itinga, Minas Gerais, Brazil: crystal chemistry and Rietveld refinement. Am. Mineral. 96, 1455–1460.

Internet Links for Rankamaite

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    • Localities for Rankamaite

    The map shows a selection of localities that have latitude and longitude coordinates recorded. Click on the symbol to view information about a locality. The symbol next to localities in the list can be used to jump to that position on the map.
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    (TL) indicates type locality. ? indicates mineral may be doubtful at this locality. All other localities listed without reference should be considered as uncertain and unproven until references can be found.
    Brazil
     
    • Minas Gerais
      • Jequitinhonha valley
        • Itinga
          • Monte Belo
    		Daniel Atencio, Reynaldo R. Contreira Fo., Stuart J. Mills, Jose M.V. Coutinho, Sara B. Honorato, Alejandro P. Ayala, Javier Ellena, and Marcelo B. de Andrade (2011) Rankamaite from the Urubu pegmatite, Itinga, Minas Gerais, Brazil: crystal chemistry and Rietveld refinement. Am. Mineral. 96, 1455–1460.
    Democratic Republic of Congo (Zaïre)
     
    • Nord-Kivu
      • Masisi Mts
    		Bul. Geol. Soc. Fin. 41 (1969), 47
    Safiannikoff, A. and van Wambeke, L. (1961): Sur un terme plombifere du groupe pyrochlore-microlite. Bulletin de la Société Francaise de Minéralogie et de Cristallographie 84: 382-384
    Kazakhstan
     
    • Eastern Kazakhstan Province (Shyghys Qazaqstan Oblysy; Vostochno-Kazakhstanskaya Oblast')
      • Kalba Range
    		Voloshin, A.V., Pakomovskii, Ya.A., Stepanov, V.I., Tyusheva, F.N. (1983): Lithiotantite, Li,(Ta,Nb)3O8, a new mineral from granite pegmatites of Eastern Kazakhstan. Mineralogiceskij Zhurnal, 5(1), 91-95. Pekov, I. (1998) Minerals First discovered on the territory of the former Soviet Union 369p. Ocean Pictures, Moscow
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    Copyright © Jolyon Ralph and Ida Chau 1993-2011. Site Map. Locality, mineral & photograph data are the copyright of the individuals who submitted them. Further information contact the Site hosted & developed by Jolyon Ralph. Mindat.org is an online information resource dedicated to providing free mineralogical information to all. Mindat relies on the contributions of hundreds of members and supporters. Mindat does not offer minerals for sale. If you would like to add information to improve the quality of our database, then click here to register.
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