Zimbabweite Mineral Data

General Zimbabweite Information

Chemical Formula:

Na(Pb,Na,K)2(Ta,Nb,Ti)4As+++4O18

Composition:

Molecular Weight = 1,498.05 gm

Potassium 1.30 % K 1.57 % K₂O

Sodium 2.30 % Na 3.10 % Na₂O

Tantalum 38.65 % Ta 47.20 % Ta₂O₅

Titanium 0.96 % Ti 1.60 % TiO₂

Niobium 3.72 % Nb 5.32 % Nb₂O₅

Arsenic 20.01 % As 26.41 % As₂O₃

Lead 13.83 % Pb 14.37 % Pb₂O

Oxygen 19.22 % O

______ ______

100.00 % 99.57 % = TOTAL OXIDE

Empirical Formula:

Na_1.5K_0.5PbAs₄Ta_3.2Nb_0.6Ti_0.3O₁₈

Environment:

In a kaolinized pegmatite.

IMA Status:

Approved IMA 1986

Locality:

St. Ann's mine, Karoi district, SE of Miami, Zimbabwe. Link to MinDat.org Location Data.

Name Origin:

Named for the country of origin.

Name Pronunciation:

Zimbabweite + Pronunciation

Synonym:

ICSD 202709

PDF 39-356

Zimbabweite Crystallography

Axial Ratios:

a:b:c =0.801:1:0.568

Cell Dimensions:

a = 12.245, b = 15.287, c = 8.684, Z = 4; V = 1,625.55 Den(Calc)= 6.12

Crystal System:

Orthorhombic - Dipyramidal H-M Symbol (2/m 2/m 2/m) Space Group: Ccmb

$Help on X Ray Diffraction:$ X Ray Diffraction:

By Intensity(I/I_o): 3.195(1), 2.882(0.7), 2.99(0.7),

Physical Properties of Zimbabweite

Cleavage:

{010} Perfect

Color:

Yellow brown, Honey yellow.

Density:

6.2

Diaphaneity:

Translucent

Fracture:

Brittle - Generally displayed by glasses and most non-metallic minerals.

Habit:

Euhedral Crystals - Occurs as well-formed crystals showing good external form.

Habit:

Tabular - Form dimensions are thin in one direction.

Hardness:

5-5.5 - Apatite-Knife Blade

Luminescence:

Non-fluorescent.

Luster:

Adamantine

Magnetism:

Nonmagnetic

Streak:

white

Optical Properties of Zimbabweite

Gladstone-Dale:

CI meas= -0.089 (Poor) - where the CI = (1-KPDmeas/KC)
CI calc= -0.104 (Poor) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.1797,KPDmeas= 0.1774,KC= 0.1629
Ncalc = 2 - 2.01

Optical Data:

Biaxial (+), a=2.1, 2V(Meas)=80. Dispersion r < v very strong.

Pleochroism (x):

pale yellow brown.

Pleochroism (y):

light reddish brown.

Pleochroism (z):

reddish brown.

Reflectivity

**Standardized Intensity (100%) Reflection Spectra of Zimbabweite in Air**
λ	R₁	R₂	∑ R₁(λ)	∑ R₂(λ)
470 nm	17.60	17.80
546 nm	17.00	17.10
589 nm	16.60	16.70
650 nm	16.20	16.50

**Calculated Relative Intensity Colors of Zimbabweite in Air**
Relative Intensity	0%	60%	100%	120%	180%	240%	300%	360%	420%	480%	530%
R₁
R₂

Calculated Properties of Zimbabweite

Electron Density:

Bulk Density (Electron Density)=5.37 gm/cc
note: Specific Gravity of Zimbabweite =6.20 gm/cc.

Fermion Index:

Fermion Index = 0.03
Boson Index = 0.97

Photoelectric:

PE_Zimbabweite= 726.01 barns/electron
U=PE_Zimbabweite x r_electron=3,898.95 barns/cc.

Radioactivity:

GRapi = 16.29 (Gamma Ray American Petroleum Institute Units)
Concentration of Zimbabweite per GRapi unit = 6.14 (%)

Estimated Radioactivity from Zimbabweite - barely detectable

Zimbabweite Classification

Dana Class:

08.07.10.01 (08)Multiple Oxides with Nb, Ta, and Ti

(08.07)Dana Type

(08.07.10)Dana Group

08.07.10.01 Zimbabweite Na(Pb,Na,K)2(Ta,Nb,Ti)4As4O18 Ccmb 2/m 2/m 2/m

Strunz Class:

04.JA.40 04 - OXIDES (Hydroxides, V[5,6] vanadates, arsenites, antimonites, bismuthites, sulfites, selenites, tellurites, iodate

04.J - Arsenites, Antimonites, Bismuthites, Sulfites,

04.JA -Arsenites, antimonites, bismuthites; without additional anions, without H2O

04.JA.40 Zimbabweite Na(Pb,Na,K)2(Ta,Nb,Ti)4As4O18 Ccmb 2/m 2/m 2/m

Other Zimbabweite Information

References:

NAME( Dana8) PHYS. PROP.(Dana8) OPTIC PROP.(AntBidBlaNic3, Dana8)

See Also:

Links to other databases for Zimbabweite :
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
15 - WWW-MINCRYST

Search for Zimbabweite using:

[AOL] [Bing] [Dog Pile] [GeoScienceWorld] [HotBot] [Ixquick] [Lycos] [MAMMA] [Scirus] [Teoma] [WebCrawler] [Wikipedia] [YAHOO]

Visit our Advertisers for Zimbabweite :

Ask about Zimbabweite here :
Ask-A-Mineralogist from the Mineralogical Society of America
Mindat.org's Discussion Groups
Original Rockhounds Discussion Group
Rockhounds Discussion Group on Yahoo Groups
Mineral Discussion Forum from Fabre Minerals - also available in Español

Print or Cut-and-Paste your Zimbabweite Specimen Label here :

Zimbabweite

Na(Pb,Na,K)2(Ta,Nb,Ti)4As+++4O18
Dana No: 08.07.10.01 Strunz No: 04.JA.40
Locality:

Notes:

Dakota Matrix
Excalibur Minerals
Exceptional Minerals
Hudson Insitute
John Betts Fine Minerals
Mc Dougall Minerals
Mineral News
Rock and Mineral Shows
Weinrich Minerals, Inc.