Simpsonite Mineral Data

Simpsonite Mineral Data +

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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.

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 - PyramidalH-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),

Crystal Structure:

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drag1 - LMB Manipulate Structure
drag2 - RMB Resize/Rotate
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H - Help Screen
I - Data Info
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Ercit T S , Cerny P , Hawthorne F C , The Canadian Mineralogist , 30 (1992) p.663-671, The crystal chemistry of simpsonite

Physical Properties of Simpsonite

Cleavage:

None

Color:

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

Density:

6.7

Diaphaniety:

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.

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

Optical Data:

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

Calculated Properties of Simpsonite

Electron Density:

r_electron=5.63 gm/cc
note: r_Simpsonite=6.35 gm/cc.

Fermion Index

Fermion Index = 0.00019
Boson Index = 0.99981

Photoelectric:

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

Radioactivity:

GRapi = 0 (Gamma Ray American Petroleum Institute Units)

Simpsonite is Not Radioactive

Simpsonite Classification

Dana Class:

8.7.5.1 (8)Multiple Oxides with Nb, Ta, and Ti

(8.7)Dana Type

(8.7.5)Dana Group

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

Strunz Class:

IV/D.27-20 IV - Oxides

IV/D - Oxides with metal : oxygen = 1:2 (MO2 and related compounds)

IV/D.27 - Bahianite - Sosedkoite series

IV/D.27-10 Bahianite Al5Sb3O14(OH)2 C 2/m 2/m

IV/D.27-20 Simpsonite Al4(Ta,Nb)3O13(OH) P 3 3

IV/D.27-30 Alumotantite AlTaO4 P bcn 2/m 2/m 2/m

IV/D.27-40 Rankamaite (Na,K,Pb,Li)3(Ta,Nb,Al)11(O,OH)30 Pban 2/m 2/m 2/m

IV/D.27-50 Sosedkoite (K,Na)5Al2(Ta,Nb)22O60 Pban 2/m 2/m 2/m

Other Simpsonite Information

References:

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

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

Simpsonite

Al4(Ta,Nb)3O13(OH)
Dana No: 8.7.5.1 Strunz No: IV/D.27-20
Locality:

Notes: