Simpsonite Mineral Data

General Simpsonite Information

Chemical Formula:

Al4(Ta,Nb)3O13(OH)

Composition:

Molecular Weight = 813.65 gm

Tantalum 53.37 % Ta 65.17 % Ta₂O₅

Niobium 5.71 % Nb 8.17 % Nb₂O₅

Aluminum 13.26 % Al 25.06 % Al₂O₃

Hydrogen 0.12 % H 1.11 % H₂O

Oxygen 27.53 % O

______ ______

100.00 % 99.51 % = TOTAL OXIDE

Empirical Formula:

Al₄Ta_2.4Nb_0.5O₁₃(OH)

Environment:

Accessory mineral in some tantalum-rich granite pegmatites.

IMA Status:

Valid Species (Pre-IMA) 1938

Locality:

Tabba Tabba, Western Australia. Link to MinDat.org Location Data.

Name Origin:

Named for Edward Sydney Simpson (1875-1939), Western Australian government mineralogis and mineral analyst.

Name Pronunciation:

Simpsonite + Pronunciation

Synonym:

ICSD 67673

PDF 15-705

Simpsonite Image

Images:

Simpsonite

Comments: Translucent pale pink simpsonite crystal fragment.
Location: Alto do Giz, Equidor, Rio Grande do Sol, Brazil. Scale: See Photo.
© Jeff Weissman / Photographic Guide to Mineral Species

Simpsonite Crystallography

Axial Ratios:

a:c = 1:0.6119

Cell Dimensions:

a = 7.377, c = 4.514, Z = 1; V = 212.74 Den(Calc)= 6.35

Crystal System:

Trigonal - Pyramidal H-M Symbol (3) Space Group: P 3

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

By Intensity(I/I_o): 1.64(1), 1.39(0.95), 2.84(0.85),

Physical Properties of Simpsonite

Cleavage:

None

Color:

Brownish yellow, Colorless, White, Light brown, Light yellow.

Density:

6.7

Diaphaneity:

Transparent

Fracture:

Brittle - Conchoidal - Very brittle fracture producing small, conchoidal fragments.

Habit:

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

Habit:

Prismatic - Crystals Shaped like Slender Prisms (e.g. tourmaline).

Habit:

Striated - Parallel lines on crystal surface or cleavage face.

Hardness:

7-7.5 - Quartz-Garnet

Luminescence:

Fluorescent, Short UV=blue white, yellowish blue pale yellow, Long UV=blue white, yellowish blue pale yellow.

Luster:

Vitreous - Adamantine

Streak:

white

Optical Properties of Simpsonite

Dichroism (e):

colorless.

Dichroism (w):

colorless.

Gladstone-Dale:

CI meas= 0.122 (Poor) - where the CI = (1-KPDmeas/KC)
CI calc= 0.074 (Fair) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.163,KPDmeas= 0.1545,KC= 0.1759
Ncalc = 2.12 - 2.18

Optical Data:

Uniaxial (-), e=2.025, w=2.045, bire=0.0200.

Calculated Properties of Simpsonite

Electron Density:

Bulk Density (Electron Density)=5.63 gm/cc
note: Specific Gravity of Simpsonite =6.35 gm/cc.

Fermion Index:

Fermion Index = 0.0001963736
Boson Index = 0.9998036264

Photoelectric:

PE_Simpsonite= 629.45 barns/electron
U=PE_Simpsonite x rElectron Density=3,543.83 barns/cc.

Radioactivity:

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

Simpsonite Classification

Dana Class:

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

(08.07)Dana Type

(08.07.05)Dana Group

08.07.05.01 Simpsonite Al4(Ta,Nb)3O13(OH) P 3 3

Strunz Class:

04.DC.10 04 - OXIDES (Hydroxides, V[5,6] vanadates, arsenites, antimonites, bismuthites, sulfites, selenites, tellurites, iodate

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

04.DC -With medium-sized cations; sheets of edge-sharing octahedra

04.DC.10 Simpsonite Al4(Ta,Nb)3O13(OH) P 3 3

Other Simpsonite Information

References:

NAME( AntBidBlaNic3) PHYS. PROP.(Enc. of Minerals,2nd ed.,1990) OPTIC PROP.(AntBidBlaNic3)

See Also:

Links to other databases for Simpsonite :
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

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Simpsonite

Al4(Ta,Nb)3O13(OH)
Dana No: 08.07.05.01 Strunz No: 04.DC.10
Locality:

Notes:

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