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Sigloite

A valid IMA mineral species
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07743670017271926532646.jpg
Sigloite

Siglo Veinte Mine, Llallagua, Rafael Bustillo Province, Potosí, Bolivia
07605150017271926565478.jpg
Sigloite, etc.

Siglo Veinte Mine, Llallagua, Rafael Bustillo Province, Potosí, Bolivia
04458130017271926689775.jpg
Sigloite

Siglo Veinte Mine, Llallagua, Rafael Bustillo Province, Potosí, Bolivia
07743670017271926532646.jpg
Sigloite

Siglo Veinte Mine, Llallagua, Rafael Bustillo Province, Potosí, Bolivia
07605150017271926565478.jpg
Sigloite, etc.

Siglo Veinte Mine, Llallagua, Rafael Bustillo Province, Potosí, Bolivia
04458130017271926689775.jpg
Sigloite

Siglo Veinte Mine, Llallagua, Rafael Bustillo Province, Potosí, Bolivia
07743670017271926532646.jpg
Sigloite

Siglo Veinte Mine, Llallagua, Rafael Bustillo Province, Potosí, Bolivia
07605150017271926565478.jpg
Sigloite, etc.

Siglo Veinte Mine, Llallagua, Rafael Bustillo Province, Potosí, Bolivia
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About SigloiteHide

04688490017271926743737.jpg
Siglo XX Mine, underground mining scene, ca. 1910

Siglo Veinte Mine, Llallagua, Rafael Bustillo Province, Potosí, Bolivia
Formula:
Fe3+Al2(PO4)2(OH)3 · 7H2O
Colour:
Light brown, straw-yellow, pale brownish orange
Hardness:
3
Specific Gravity:
2.35
Crystal System:
Triclinic
Name:
Named after its discovery locality, the Siglo Veinte Mine (Siglo XX Mine), Llallagua, Bustillos Province, Potosí Department, Bolivia.
This page provides mineralogical data about Sigloite.


Unique IdentifiersHide

Mindat ID:
3657
Long-form identifier:
mindat:1:1:3657:9

Similar NamesHide

IgloiteA synonym of Aragonite
SkoliteA variety of 'Glauconite'H4K(Mg,Fe2+,Ca)(Al,Fe3+)3Si6O20 · 4H2O

Classification of SigloiteHide

05521570017685316117551.jpg
Laueite structure archetype

In sigloite, the M1 site is occupied by Fe3+ and the M2 and M3 sites are occupied by Al3+. The X site is a phosphate group and the structure is additionally hydroxylated compared to the other laueite supergroup members to balance the additional positive charge at the M1 site (which is typically only a +2 cation).

IMA Classification of SigloiteHide

IMA status:
Approved
First published:
1962
Type description reference:
Hurlbut, Cornelius S., Honea, Russell (1962) Sigloite, a new mineral from Llallagua, Bolivia. American Mineralogist, 47 (1-2) 1-8
Strunz-mindat (2026):
8.DC.30

8 : PHOSPHATES, ARSENATES, VANADATES
D : Phosphates, etc. with additional anions, with H2O
C : With only medium-sized cations, (OH, etc.):RO4 = 1:1 and < 2:1
Dana 8th ed.:
42.11.14.3

42 : HYDRATED PHOSPHATES, ETC.CONTAINING HYDROXYL OR HALOGEN
11 : (AB)3(XO4)2Zq·xH2O
Hey's CIM Ref.:
19.14.26

19 : Phosphates
14 : Phosphates of Fe and other metals

Mineral SymbolsHide

As of 2021 there are now IMA–CNMNC approved mineral symbols (abbreviations) for each mineral species, useful for tables and diagrams.

SymbolSourceReference for Standard
SigIMA–CNMNCWarr, L.N. (2021). IMA–CNMNC approved mineral symbols. Mineralogical Magazine, 85(3), 291-320. doi:10.1180/mgm.2021.43

Pronunciation of SigloiteHide

Pronunciation:
PlayRecorded byCountry
Jolyon RalphUnited Kingdom

Physical Properties of SigloiteHide

Transparency:
Translucent
Colour:
Light brown, straw-yellow, pale brownish orange
Hardness:
3 on Mohs scale
Cleavage:
Perfect
On {010}, perfect; on {001}, good
Density:
2.35 g/cm3 (Measured)    2.40 g/cm3 (Calculated)

Optical Data of SigloiteHide

Type:
Biaxial (+)
RI values:
nα = 1.563 nβ = 1.586(1) nγ = 1.619
2V:
Measured: 76° , Calculated: 82°
Max. Birefringence:
δ = 0.056
Based on recorded range of RI values above.

Interference Colours:
The colours simulate birefringence patterns seen in thin section under crossed polars. They do not take into account mineral colouration or opacity.

Michel-Levy Bar The default colours simulate the birefringence range for a 30 µm thin-section thickness. Adjust the slider to simulate a different thickness.

Grain Simulation You can rotate the grain simulation to show how this range might look as you rotated a sample under crossed polars.

Surface Relief:
Moderate
Dispersion:
strong
Optical Extinction:
X (90°,32°); Y (–144°,70°); Z (–46°,66°) [using (φ,ρ)]

Chemistry of SigloiteHide

Mindat Formula:
Fe3+Al2(PO4)2(OH)3 · 7H2O
Element Weights:
Element% weight
O60.390 %
P12.990 %
Fe11.711 %
Al11.316 %
H3.593 %

Calculated from ideal end-member formula.
Elements listed:
Al, Fe, H, O, P - search for minerals with similar chemistry

Crystallography of SigloiteHide

Crystal System:
Triclinic
Class (H-M):
1 - Pinacoidal
Space Group:
P1
Cell Parameters:
a = 5.190(2) Å, b = 10.419(4) Å, c = 7.033(3) Å
α = 105.00(3)°, β = 111.31(3)°, γ = 6970.87(3)°
Ratio:
a:b:c = 0.498 : 1 : 0.675
Unit Cell V:
190.03 ų (Calculated from Unit Cell)
Z:
1
Morphology:
Forms include {001}, {010}, {100}, {110}, {110}, {120}, {011}, {111}, {112}.

Crystal StructureHide

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IDSpeciesReferenceLinkYearLocalityPressure (GPa)Temp (K)
0014617SigloiteHawthorne F C (1988) Sigloite: The oxidation mechanism in [M2(PO4)2(OH)2(H21O)2] structures Mineralogy and Petrology 38 201-2111988Siglo XX Mine, Llallagau, Bolivia0293
CIF Raw Data - click here to close

X-Ray Powder DiffractionHide

Loading XRD data...
Data Set:
Data courtesy of RRUFF project at University of Arizona, used with permission.
Powder Diffraction Data:
d-spacingIntensity
9.69 Å(100)
6.46 Å(90)
4.86 Å(90)
3.23 Å(70)
2.82 Å(60)
2.56 Å(50)
4.68 Å(40b)

Geological EnvironmentHide

Paragenetic Mode(s):
Paragenetic ModeEarliest Age (Ga)
High-? alteration and/or metamorphism
31 : Thermally altered carbonate, phosphate, and iron formations
Stage 7: Great Oxidation Event<2.4
47a : [Near-surface hydration of prior minerals]
47c : [Carbonates, phosphates, borates, nitrates]

Type Occurrence of SigloiteHide

Type Locality:
ⓘ Siglo Veinte Mine, Llallagua, Rafael Bustillo Province, Potosí, Bolivia
General Appearance of Type Material:
Cavities filled with straw yellow intergrowths of crystals and crystals perched on wavellite overgrowths on quartz.
Place of Conservation of Type Material:
Harvard University, Cambridge, Massachusetts, 107443; National Museum of Natural History, Washington, D.C., USA, 115320.
Associated Minerals at Type Locality:
ChildreniteCrandalliteMetavauxiteQuartzVauxite
Wavellite
Reference:
Hurlbut, Cornelius S., Honea, Russell (1962) Sigloite, a new mineral from Llallagua, Bolivia. American Mineralogist, 47 (1-2) 1-8

Synonyms of SigloiteHide

Other Language Names for SigloiteHide

Dutch:Sigloiet
German:Sigloit
Spanish:Sigloita

Relationship of Sigloite to other SpeciesHide

Member of:
Laueite Group > Laueite Supergroup
Other Members of Laueite Group:
FerrolaueiteFe2+Fe3+2(PO4)2(OH)2 · 8H2OTric. 1 : P1
GordoniteMgAl2(PO4)2(OH)2 · 8H2OTric. 1 : P1
Kastningite(Mn2+,Fe2+,Mg)Al2(PO4)2(OH)2 · 8H2OTric. 1 : P1
KummeriteMn2+Fe3+Al(PO4)2(OH)2 · 8H2OTric. 1 : P1
LaueiteMn2+Fe3+2(PO4)2(OH)2 · 8H2OTric. 1 : P1
MangangordoniteMn2+Al2(PO4)2(OH)2 · 8H2OTric. 1 : P1
ParavauxiteFe2+Al2(PO4)2(OH)2 · 8H2OTric. 1 : P1
StewartiteMn2+Fe3+2(PO4)2(OH)2 · 8H2OTric. 1 : P1
UshkoviteMgFe3+2(PO4)2(OH)2 · 8H2OTric. 1 : P1

Common AssociatesHide

Associations Based on Photo Data:
399 photos of Sigloite associated with ParavauxiteFe2+Al2(PO4)2(OH)2 · 8H2O
101 photos of Sigloite associated with VauxiteFe2+Al2(PO4)2(OH)2 · 6H2O
95 photos of Sigloite associated with MetavauxiteFe2+Al2(PO4)2(OH)2 · 8H2O
40 photos of Sigloite associated with WavelliteAl3(PO4)2(OH)3 · 5H2O
20 photos of Sigloite associated with PyriteFeS2
17 photos of Sigloite associated with QuartzSiO2
14 photos of Sigloite associated with FranckeiteFe2+(Pb,Sn2+)6Sn4+2Sb2S14
8 photos of Sigloite associated with GreenockiteCdS
5 photos of Sigloite associated with RömeriteFe2+Fe3+2(SO4)4 · 14H2O
1 photo of Sigloite associated with ChildreniteFe2+Al(PO4)(OH)2 · H2O

Related Minerals - Strunz-mindat GroupingHide

8.DC.FerroberauniteFe2+Fe3+5(PO4)4(OH)5 · 6H2OMon. 2/m : B2/b
8.DC.CésarferreiraiteFe2+ Fe3+2(AsO4)2(OH)2 · 8H2OTric. 1 : P1
8.DC.FerrivauxiteFe3+Al2(PO4)2(OH)3 · 5H2OTric. 1 : P1
8.DC.IanbruceiteZn2(AsO4)(OH) · 3H2OMon. 2/m : P21/b
8.DC.05NissoniteCu2Mg2(PO4)2(OH)2 · 5H2OMon. 2/m : B2/b
8.DC.07EuchroiteCu2(AsO4)(OH) · 3H2OOrth. 2 2 2 : P21 21 21
8.DC.10LegranditeZn2(AsO4)(OH) · H2OMon. 2/m : P21/b
8.DC.12StrashimiriteCu8(AsO4)4(OH)4 · 5H2OMon.
8.DC.15EarlshannoniteMn2+Fe3+2(PO4)2(OH)2 · 4H2OMon. 2/m : P21/b
8.DC.15KunatiteCuFe3+2(PO4)2(OH)2 · 4H2OMon. 2/m : P21/b
8.DC.15'UM2006-27-PO:FeHZn'ZnFe3+2(PO4)2(OH)2 · 4H2OMon.
8.DC.15'UKI-2006-(PO:AlCuFeH)'Fe2+Al3+2(PO4)2(OH)2 · 4H2O
8.DC.15CobaltarthuriteCoFe3+2(AsO4)2(OH)2 · 4H2OMon. 2/m : P21/b
8.DC.15ArthuriteCuFe3+2(AsO4)2(OH)2 · 4H2OMon. 2/m : P21/b
8.DC.15OjuelaiteZnFe3+2(AsO4)2(OH)2 · 4H2OMon. 2/m : P21/b
8.DC.15WhitmoreiteFe2+Fe3+2(PO4)2(OH)2 · 4H2OMon. 2/m : P21/b
8.DC.15BendadaiteFe2+Fe3+2(AsO4)2(OH)2 · 4H2OMon. 2/m : P21/b
8.DC.17KleemaniteZnAl2(PO4)2(OH)2 · 3H2OMon.
8.DC.20MagnesiobermaniteMgMn3+2(PO4)2(OH)2 · 4H2OMon. 2 : P21
8.DC.20BermaniteMn2+Mn3+2(PO4)2(OH)2 · 4H2OMon. 2/m : P2/b
8.DC.20CoralloiteMn2+Mn3+2(AsO4)2(OH)2 · 4H2OTric. 1 : P1
8.DC.22KovdorskiteMg2(PO4)(OH) · 3H2OMon. 2/m : P21/b
8.DC.25ZincostrunziteZnFe3+2(PO4)2(OH)2 · 6.5H2OTric. 1 : P1
8.DC.25MetavauxiteFe2+Al2(PO4)2(OH)2 · 8H2OMon. 2/m : P21/b
8.DC.25MetavivianiteFe2+Fe3+2(PO4)2(OH)2 · 6H2OTric. 1 : P1
8.DC.25FerristrunziteFe3+Fe3+2(PO4)2(OH)3 · 5H2OTric.
8.DC.25StrunziteMn2+Fe3+2(PO4)2(OH)2 · 6H2OTric. 1 : P1
8.DC.25FerrostrunziteFe2+Fe3+2(PO4)2(OH)2 · 6H2OTric.
8.DC.27BerauniteFe3+6(PO4)4O(OH)4 · 6H2OMon. m : Bb
8.DC.27TvrdýiteFe2+Fe3+2Al3(PO4)4(OH)5(H2O)4 · 2H2OMon. 2/m : B2/b
8.DC.27ZincoberauniteZnFe3+5(PO4)4(OH)5 · 6H2OMon. 2/m : B2/b
8.DC.30MaghrebiteMgAl2(AsO4)2(OH)2 · 8H2OTric. 1 : P1
8.DC.30FerrolaueiteFe2+Fe3+2(PO4)2(OH)2 · 8H2OTric. 1 : P1
8.DC.30UshkoviteMgFe3+2(PO4)2(OH)2 · 8H2OTric. 1 : P1
8.DC.30LaueiteMn2+Fe3+2(PO4)2(OH)2 · 8H2OTric. 1 : P1
8.DC.30ParavauxiteFe2+Al2(PO4)2(OH)2 · 8H2OTric. 1 : P1
8.DC.30NordgauiteMnAl2(PO4)2(F,OH)2 · 5H2OTric. 1 : P1
8.DC.30Kayrobertsonite[MnAl2(PO4)2(OH)2(H2O)4] · 2H2OTric. 1 : P1
8.DC.30KummeriteMn2+Fe3+Al(PO4)2(OH)2 · 8H2OTric. 1 : P1
8.DC.30MangangordoniteMn2+Al2(PO4)2(OH)2 · 8H2OTric. 1 : P1
8.DC.30StewartiteMn2+Fe3+2(PO4)2(OH)2 · 8H2OTric. 1 : P1
8.DC.30GordoniteMgAl2(PO4)2(OH)2 · 8H2OTric. 1 : P1
8.DC.30Kastningite(Mn2+,Fe2+,Mg)Al2(PO4)2(OH)2 · 8H2OTric. 1 : P1
8.DC.30PseudolaueiteMn2+Fe3+2(PO4)2(OH)2 · 8H2OMon. 2/m : P21/b
8.DC.32KamarizaiteFe3+3(AsO4)2(OH)3 · 3H2OTric. 1 : P1
8.DC.32TinticiteFe3+3(PO4)2(OH)3 · 3H2OTric. 1 : P1
8.DC.35VauxiteFe2+Al2(PO4)2(OH)2 · 6H2OTric. 1 : P1
8.DC.37VantasseliteAl4(PO4)3(OH)3 · 9H2OOrth.
8.DC.40CacoxeniteFe3+24AlO6(PO4)17(OH)12 · 75H2OHex. 6/m : P63/m
8.DC.45SouzaliteMg3Al4(PO4)4(OH)6 · 2H2OTric. 1
8.DC.45Gormanite(Fe2+,Mg)3(Al,Fe3+)4(PO4)4(OH)6 · 2H2OTric.
8.DC.47KingiteAl3(PO4)2F2(OH) · 7H2OTric.
8.DC.50AllanpringiteFe3+3(PO4)2(OH)3 · 5H2OMon. 2/m : P21/m
8.DC.50FluorwavelliteAl3(PO4)2(OH)2F · 5H2OOrth. mmm (2/m 2/m 2/m)
8.DC.50WavelliteAl3(PO4)2(OH)3 · 5H2OOrth. mmm (2/m 2/m 2/m)
8.DC.52KribergiteAl5(PO4)3(SO4)(OH)4 · 4H2OTric. 1 : P1
8.DC.55MapimiteZn2Fe3+3(AsO4)3(OH)4 · 10H2OMon. m : Bm
8.DC.57OgdensburgiteCa2Fe3+4(Zn,Mn2+)(AsO4)4(OH)6 · 6H2OOrth. mmm (2/m 2/m 2/m) : Cmmm
8.DC.60CloncurryiteCu0.5(VO)0.5Al2(PO4)2F2 · 5H2OMon. 2/m : P21/b
8.DC.60Nevadaite(Cu2+,Al,V3+)6Al8(PO4)8F8(OH)2 · 22H2OOrth. mmm (2/m 2/m 2/m)
8.DC.62KenngottiteMn2+3Fe3+4(PO4)4(OH)6(H2O)2 Mon. 2/m : P2/b
8.DC.67MolinelloiteCu(H2O)(OH)V4+O(V5+O4)Tric. 1 : P1
8.DC.70WhitecapsiteH16Fe2+5Fe3+14Sb3+6(AsO4)18O16 · 120H2OHex. 6/m : P63/m
8.DC.75HeimitePbCu2(AsO4)(OH)3 · 2H2OMon. 2/m
8.DC.80LedneviteCu[PO3(OH)] · H2OMon. 2/m : P21/b

Other InformationHide

Health Risks:
No information on health risks for this material has been entered into the database. You should always treat mineral specimens with care.

Internet Links for SigloiteHide

References for SigloiteHide

Localities for SigloiteHide

Showing 5 localities.

This map shows a selection of localities that have latitude and longitude coordinates recorded. Click on the symbol to view information about a locality. The symbol next to localities in the list can be used to jump to that position on the map.
Hide all sections | Show all sections

Locality ListHide

- This locality has map coordinates listed. - This locality has estimated coordinates. ⓘ - Click for references and further information on this occurrence. ? - Indicates mineral may be doubtful at this locality. - Good crystals or important locality for species. - World class for species or very significant. (TL) - Type Locality for a valid mineral species. (FRL) - First Recorded Locality for everything else (eg varieties). Struck out - Mineral was erroneously reported from this locality. Faded * - Never found at this locality but inferred to have existed at some point in the past (e.g. from pseudomorphs).

All localities listed without proper references should be considered as questionable.
Bolivia (TL)
 
  • Potosí
    • Rafael Bustillo Province
      • Llallagua
Palache et al. (1951) +2 other references
France
 
  • Occitanie
    • Tarn
      • Castres
        • Fontrieu
          • Fumade
Lheur et al. (2013)
USA
 
  • Arkansas
    • Polk County
      • Shady
Josef Vajdak (2002)
    • Gaston County
Kenny Gay collection
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