Foordite Mineral Data

General Foordite Information

Chemical Formula:

Sn++(Nb,Ta)2O6

Composition:

Molecular Weight = 444.54 gm

Tantalum 20.35 % Ta 24.85 % Ta₂O₅

Niobium 31.35 % Nb 44.85 % Nb₂O₅

Tin 26.70 % Sn 30.30 % SnO

Oxygen 21.59 % O

______ ______

100.00 % 100.00 % = TOTAL OXIDE

Empirical Formula:

SnNb_1.5Ta_0.5O₆

Environment:

Alluvial pebble originating from a highly differentiated granite pegmatite, formed under reducing conditions deficient in Fe, Mn, Na, Ca, and F

IMA Status:

Approved IMA 1988

Locality:

15 km north-northwest of Lutsiro, near the Sebeya River, western Rwanda. Link to MinDat.org Location Data.

Name Origin:

Named for Eugene Edward Foord (1946-1998), American mineralogist with the U.S. Geological Survey, Denver, Colorado, USA, student of granite pegmatites.

Name Pronunciation:

Foordite

Synonym:

ICSD 202827

PDF 45-1350

Foordite Image

Images:

Foordite

Comments: Brownish massive foordite.
Location: Manono, Shaba (Katanga), Congo (ZaÃ¯re). Scale: Picture size 7 mm.
© Thomas Witzke / Abraxas-Verlag

Foordite Crystallography

Axial Ratios:

a:b:c =3.5042:1:1.1399

Cell Dimensions:

a = 17.097, b = 4.879, c = 5.562, Z = 4; beta = 90.85° V = 463.91 Den(Calc)= 6.36

Crystal System:

Monoclinic - Prismatic H-M Symbol (2/m) Space Group: C 2/c

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

By Intensity(I/I_o): 2.849(1), 3.071(0.5), 3.1(0.5),

Physical Properties of Foordite

Cleavage:

{???} Perfect

Color:

Brownish yellow.

Density:

6.734

Diaphaneity:

Translucent

Hardness:

6 - Orthoclase

Luster:

Vitreous - Adamantine

Streak:

yellow white

Optical Properties of Foordite

Gladstone-Dale:

CI meas= 0.04 (Good) - where the CI = (1-KPDmeas/KC)
CI calc= -0.017 (Superior) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.2035,KPDmeas= 0.1922,KC= 0.2001
Ncalc = 2.27 - 2.35

Optical Data:

Biaxial (+), b=2.294

Calculated Properties of Foordite

Electron Density:

Bulk Density (Electron Density)=5.61 gm/cc
note: Specific Gravity of Foordite =6.36 gm/cc.

Fermion Index:

Fermion Index = 0.04
Boson Index = 0.96

Photoelectric:

PE_Foordite= 371.30 barns/electron
U=PE_Foordite x rElectron Density=2,082.39 barns/cc.

Radioactivity:

GRapi = 0 (Gamma Ray American Petroleum Institute Units)
Foordite is Not Radioactive

Foordite Classification

Dana Class:

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

(08.03)where A (B2O6)

(08.03.10)Dana Group

08.03.10.01 Thoreaulite SnTa2O6 C 2/c 2/m

08.03.10.02 Foordite Sn(Nb,Ta)2O6 C 2/c 2/m

Strunz Class:

04.DG.15 04 - OXIDES (Hydroxides, V[5,6] vanadates, arsenites, antimonites, bismuthites, sulfites, selenites, tellurites, iodate

04.D - Metal:Oxygen = 1:2 and similar

04.DG -With large (ï¿½ medium-sized) cations; chains of edge-sharing octahedra

04.DG.15 Foordite Sn(Nb,Ta)2O6 C 2/c 2/m

04.DG.15 Thoreaulite SnTa2O6 C 2/c 2/m

Other Foordite Information

References:

NAME( AntBidBlaNic3) PHYS. PROP.(Am.Min.,Vol.75,p707,1990) OPTIC PROP.(Am.Min.,Vol.75,p707,1990)

See Also:

Links to other databases for Foordite :
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 - MinDAT
10 - Mineralienatlas (Deutsch)
11 - Online Mineral Museum
12 - QUT Mineral Atlas
13 - Ruff.Info
14 - WWW-MINCRYST

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

Foordite

Sn++(Nb,Ta)2O6
Dana No: 08.03.10.02 Strunz No: 04.DG.15
Locality:

Notes:

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