Mineralogy Database

Rankamaite Mineral Data

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General Rankamaite Information

Help on Chemical  Formula: Chemical Formula: (Na,K,Pb,Li)3(Ta,Nb,Al)11(O,OH)30
Help on Composition: Composition: Molecular Weight = 2,177.26 gm
   Potassium   1.44 %  K     1.73 % K2O
   Sodium      1.80 %  Na    2.42 % Na2O
   Lithium     0.06 %  Li    0.14 % Li2O
   Tantalum   57.34 %  Ta   70.02 % Ta2O5
   Niobium    12.80 %  Nb   18.31 % Nb2O5
   Aluminum    1.49 %  Al    2.81 % Al2O3
   Hydrogen    0.17 %  H     1.53 % H2O
   Lead        2.85 %  Pb    3.08 % PbO
   Oxygen     22.05 %  O
             ______        ______ 
             100.00 %      100.04 % = TOTAL OXIDE
Help on Empirical Formula: Empirical Formula: Na1.7K0.8Pb0.3Li0.2Ta6.9Nb3Al1.2O26.3(OH)3.7
Help on Environment: Environment: In alluvial concentrates. Probably derived from the alteration of simpsonite in a lithium pegmatite.
Help on IMA Status: IMA Status: Approved IMA 1969
Help on Locality: Locality: Mumba, Kivu, Zaire. Link to MinDat.org Location Data.
Help on Name Origin: Name Origin: Named for Kalervo Rankama (1913-), Finnish geochemist, University of Helsinki.
Help on Name Pronunciation: Name Pronunciation: Rankamaite + Pronunciation Say RANKAMAITE

Rankamaite Image

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Comments: White, massive-fibrous rankamaite.
Location: Mumba, Kivu, Congo (Zaïre). Scale: Picture size 2 mm.
© Thomas Witzke / Abraxas-Verlag

Rankamaite Crystallography

Help on Axial Ratios: Axial Ratios: a:b:c =0.9711:1:0.2222
Help on Cell Dimensions: Cell Dimensions: a = 17.19, b = 17.7, c = 3.933, Z = 2; V = 1,196.67 Den(Calc)= 6.04
Help on Crystal System: Crystal System: Orthorhombic - Dipyramidal H-M Symbol (2/m 2/m 2/m) Space Group: Pban
Help on X Ray Diffraction: X Ray Diffraction: By Intensity(I/Io): 2.97(1), 3.011(0.8), 3.375(0.6),

Physical Properties of Rankamaite

Help on Cleavage: Cleavage: None
Help on Color: Color: White, Creamy white.
Help on Density: Density: 5.5
Help on Diaphaneity: Diaphaneity: Transparent
Help on Habit: Habit: Acicular - Occurs as needle-like crystals.
Help on Habit: Habit: Fibrous - Crystals made up of fibers.
Help on Habit: Habit: Massive - Uniformly indistinguishable crystals forming large masses.
Help on Hardness: Hardness: 3-4 - Calcite-Fluorite
Help on Luster: Luster: Adamantine
Help on Streak: Streak: white

Optical Properties of Rankamaite

Help on Gladstone-Dale: Gladstone-Dale: CI meas= -0.122 (Poor) - where the CI = (1-KPDmeas/KC)
CI calc= -0.021 (Excellent) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.1821,KPDmeas= 0.2,KC= 0.1783
Ncalc = 1.98 - 2.08
Help on Optical Data: Optical Data: Biaxial (?), b=2.1

Calculated Properties of Rankamaite

Help on Electron Density: Electron Density: Bulk Density (Electron Density)=5.24 gm/cc
note: Specific Gravity of Rankamaite =6.04 gm/cc.
Help on Fermion Index: Fermion Index: Fermion Index = 0.0065339073
Boson Index = 0.9934660927
Help on Photoelectric: Photoelectric: PERankamaite = 751.78 barns/electron
U=PERankamaite x relectron=3,942.07 barns/cc.
Help on Radioactivity: Radioactivity:

GRapi = 17.98 (Gamma Ray American Petroleum Institute Units)
Concentration of Rankamaite per GRapi unit = 5.56 (%)

Estimated Radioactivity from Rankamaite - barely detectable


Rankamaite Classification

Help on  Dana Class: Dana Class: (08)Multiple Oxides with Nb, Ta, and Ti
  (08.07)Dana Type
  (08.07.06)Dana Group Rankamaite (Na,K,Pb,Li)3(Ta,Nb,Al)11(O,OH)30 Pban 2/m 2/m 2/m Sosedkoite (K,Na)5Al2(Ta,Nb)22O60 Pban 2/m 2/m 2/m
Help on  Strunz Class: Strunz Class: 04.DM.05 04 - OXIDES (Hydroxides, V[5,6] vanadates, arsenites, antimonites, bismuthites, sulfites, selenites, tellurites, iodate
  04.D - Metal:Oxygen = 1:2 and similar
  04.DM -With large (� medium-sized) cations; unclassified
04.DM.05 Rankamaite (Na,K,Pb,Li)3(Ta,Nb,Al)11(O,OH)30 Pban 2/m 2/m 2/m
04.DM.05 Sosedkoite (K,Na)5Al2(Ta,Nb)22O60 Pban 2/m 2/m 2/m

Other Rankamaite Information

Help on References: References: NAME( Dana8) PHYS. PROP.(Enc. of Minerals,2nd ed.,1990) OPTIC PROP.(Dana8)
Help on See Also: See Also: Links to other databases for Rankamaite :
1 - Am. Min. Crystal Structure Database
2 - Athena
3 - EUROmin Project
4 - Ecole des Mines de Paris
5 - GeoScienceWorld
6 - Google Images
7 - Google Scholar
8 - Handbook of Mineralogy (MinSocAm)
9 - Handbook of Mineralogy (UofA)
10 - MinDAT
11 - Mineralienatlas (Deutsch)
12 - Online Mineral Museum
13 - QUT Mineral Atlas
14 - Ruff.Info

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Dana No: Strunz No: 04.DM.05





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