Sigloite Mineral Data

General Sigloite Information

Chemical Formula:

Fe+++Al2(PO4)2(OH)3•5(H2O)

Composition:

Molecular Weight = 440.85 gm

Aluminum 12.24 % Al 23.13 % Al₂O₃

Iron 12.67 % Fe 18.11 % Fe₂O₃

Phosphorus 14.05 % P 32.20 % P₂O₅

Hydrogen 2.97 % H 26.56 % H₂O

Oxygen 58.07 % O

______ ______

100.00 % 100.00 % = TOTAL OXIDE

Empirical Formula:

Fe³⁺Al₂(PO₄)₂(OH)₃•5(H₂O)

Environment:

Pseudomorphs of oxidized (Fe3+) paravauxite.

IMA Status:

Approved IMA 1962

Locality:

Sigol XX mine, Llallagua, Potosi, Bolivia. Link to MinDat.org Location Data.

Name Origin:

Named for the locality.

Name Pronunciation:

Sigloite

Synonym:

ICSD 68095

PDF 14-171

Sigloite Image

Images:

Sigloite Vauxite

Comments: Lime green, crystalline aggregate of sigloite on massive, blue vauxite.
Location: Llallagua, Potosi Department, Bolivia. Scale: Not Given.
© Lou Perloff / Photo Atlas of Minerals

Sigloite Crystallography

Axial Ratios:

a:b:c =0.5:1:0.6711

Cell Dimensions:

a = 5.26, b = 10.52, c = 7.06, Z = 1; alpha = 106.933°, beta = 111.5°, gamma = 69.5° V = 325.70 Den(Calc)= 2.25

Crystal System:

Triclinic - PinacoidalH-M Symbol ( 1) Space Group: P1

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

By Intensity(I/I_o): 9.69(1), 4.86(0.9), 6.46(0.9),

Crystal Structure:

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Hawthorne F C , Mineralogy and Petrology , 38 (1988) p.201-211, Sigloite: The oxidation mechanism in [M2(PO4)2(OH)2(H21O)2] structures, Locality: Siglo XX Mine, Llallagau, Bolivia

Physical Properties of Sigloite

Cleavage:

{100} Perfect, {001} Good

Color:

Brown, Light brown, Light yellow, Straw yellow.

Density:

2.35

Diaphaneity:

Transparent

Habit:

Pseudomorphous - Occurs in the form of another mineral.

Hardness:

3 - Calcite

Luster:

Vitreous - Pearly

Streak:

white

Optical Properties of Sigloite

Gladstone-Dale:

CI meas= 0.013 (Superior) - where the CI = (1-KPDmeas/KC)
CI calc= -0.059 (Good) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.2691,KPDmeas= 0.2508,KC= 0.2542
Ncalc = 1.56 - 1.6

Optical Data:

Biaxial (+), a=1.563, b=1.586, g=1.619, bire=0.0560, 2V(Calc)=82, 2V(Meas)=76. Dispersion r < v.

Calculated Properties of Sigloite

Electron Density:

Bulk Density (Electron Density)=2.38 gm/cc
note: Specific Gravity of Sigloite =2.35 gm/cc.

Fermion Index:

Fermion Index = 0.0029687958
Boson Index = 0.9970312042

Photoelectric:

PE_Sigloite= 4.75 barns/electron
U=PE_Sigloite x rElectron Density= 11.29 barns/cc.

Radioactivity:

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

Sigloite Classification

Dana Class:

42.11.14.03 (42)Hydrated Phosphates, etc., Containing Hydroxyl or Halogen

(42.11)where (AB)4 (XO4)3 Zq · x(H2O)

(42.11.14)Vauxite Group

42.11.14.01 Vauxite FeAl2(PO4)2(OH)2•6(H2O) P1 1

42.11.14.02 Paravauxite FeAl2(PO4)2(OH)2•8(H2O) P1 1

42.11.14.03 Sigloite FeAl2(PO4)2(OH)3•5(H2O) P1 1

42.11.14.04 Gordonite MgAl2(PO4)2(OH)2•8(H2O) P1 1

42.11.14.05 Mangangordonite (Mn,Fe,Mg)Al2(PO4)2(OH)2•8(H2O) P1 1

42.11.14.06 Kastningite! (Mn,Fe,Mg)Al2(PO4)2(OH)2•8(H2O) P1 1

42.11.14.07 Maghrebite! MgAl2(AsO4)2(OH)2•8H2O P1 1

Strunz Class:

08.DC.30 08 - PHOSPHATES, ARSENATES, VANADATES

08.D - Phosphates, etc

08.DC -With only medium-sized cations, (OH, etc.):RO4 = 1:1 and < 2:1

08.DC.30 Gordonite MgAl2(PO4)2(OH)2•8(H2O) P1 1

08.DC.30 Ferrolaueite! FeFe2(PO4)2(OH)2•8(H2O) Tri

08.DC.30 Mangangordonite (Mn,Fe,Mg)Al2(PO4)2(OH)2•8(H2O) P1 1

08.DC.30 Laueite MnFe2(PO4)2(OH)2•8(H2O) P1 1

08.DC.30 Sigloite FeAl2(PO4)2(OH)3•5(H2O) P1 1

08.DC.30 Pseudolaueite MnFe2(PO4)2(OH)2•7-8(H2O) P 2₁/a 2/m

08.DC.30 Paravauxite FeAl2(PO4)2(OH)2•8(H2O) P1 1

08.DC.30 Stewartite MnFe2(PO4)2(OH)2•8(H2O) P1 1

08.DC.30 Ushkovite MgFe2(PO4)2(OH)2•8(H2O) P1 1

08.DC.30 Kastningite! (Mn,Fe,Mg)Al2(PO4)2(OH)2•8(H2O) P1 1

08.DC.30 Maghrebite! MgAl2(AsO4)2(OH)2•8H2O P1 1

Other Sigloite Information

References:

NAME( Dana8) PHYS. PROP.(Enc. of Minerals,2nd ed.,1990) OPTIC PROP.(Dana8)

See Also:

Links to other databases for Sigloite :
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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Ask about Sigloite here :
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Print or Cut-and-Paste your Sigloite Specimen Label here :

Sigloite

Fe+++Al2(PO4)2(OH)3•5(H2O)
Dana No: 42.11.14.03 Strunz No: 08.DC.30
Locality:

Notes: