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Halloysite

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Jean-Baptiste-Julien d'Omalius d'Halloy(1783-1875)
Formula:
Al2(Si2O5)(OH)4
Colour:
White to tan, sometimes greenish or bluish, also chocolate brown to reddish.
Lustre:
Waxy, Earthy
Hardness:
1 - 2
Specific Gravity:
2 - 2.65
Crystal System:
Monoclinic
Name:
Named after the Belgian geologist Jean-Baptiste d'Omalius d'Halloy, (February 16th 1783 - January 15th 1875), who discovered the mineral. He was a nobleman, a statesman, and pioneer of modern geology in Belgium.
Typically found as earthy to somewhat waxy looking extremely fine-grained clayey masses, white to tan and also occasionally bluish or greenish.

The name halloysite currently stands for the two grandfathered and distinct species Halloysite-7Å and Halloysite-10Å.
Halloysite-10Å is also known as "endellite" in European literature and considered to be a hydrated mineral - the "hydrated halloysite" of North American literature.

"Metahalloysite" (= Halloysite-7Å) is dehydrated halloysite and characterised by a reduced interlayer spacing.

Originally reported from Angleur, Liège, Liège Province, Belgium.

Also reported as a biomineral formed by the action of lichen (e.g., Lasallia spp., Mucor spp., etc.) on cave deposits and waters (vide Burford et al., 2003).


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Classification of HalloysiteHide

9.ED.10

9 : SILICATES (Germanates)
E : Phyllosilicates
D : Phyllosilicates with kaolinite layers composed of tetrahedral and octahedral nets
Dana 7th ed.:
71.1.1.4
71.1.1.4

71 : PHYLLOSILICATES Sheets of Six-Membered Rings
1 : Sheets of 6-membered rings with 1:1 layers
15.10

15 : Silicates of Aluminum

Physical Properties of HalloysiteHide

Waxy, Earthy
Transparency:
Translucent, Opaque
Colour:
White to tan, sometimes greenish or bluish, also chocolate brown to reddish.
Streak:
Paler than the color, or white.
Hardness:
1 - 2 on Mohs scale
Fracture:
Sub-Conchoidal
Density:
2 - 2.65 g/cm3 (Measured)    2.14 g/cm3 (Calculated)

Optical Data of HalloysiteHide

Type:
Biaxial
RI values:
nα = 1.553 - 1.565 nβ = 1.559 - 1.569 nγ = 1.560 - 1.570
Max Birefringence:
δ = 0.007
Image shows birefringence interference colour range (at 30µm thickness)
and does not take into account mineral colouration.
Surface Relief:
Low
Dispersion:
r < v moderate

Chemical Properties of HalloysiteHide

Formula:
Al2(Si2O5)(OH)4
Common Impurities:
Ti,Ca,Na,K,Fe,Cr,Mg,Ni,Cu

Crystallography of HalloysiteHide

Crystal System:
Monoclinic
Class (H-M):
m - Domatic
Space Group:
Bb
Cell Parameters:
a = 5.14 Å, b = 8.9 Å, c = 7.214 Å
β = 99.7°
Ratio:
a:b:c = 0.578 : 1 : 0.811
Unit Cell V:
325.29 ų (Calculated from Unit Cell)
Z:
2
Morphology:
Typically found as extremely fine-grained clayey masses. The two "forms" Halloysite-7Å and Halloysite-10Å are the most common. It has a tubular morphology at the nanometer scale.

X-Ray Powder DiffractionHide

Powder Diffraction Data:
d-spacingIntensity
Halloysite-7A (1)
(
7.5(90)
4.42(100)
3.63(90)
2.56(80)
1.68(80)
1.48(90)
1.28(70)
1.23(70)
________(
(
Halloysite-7A (2)
(
7.3(65)
4.42(100)
3.62(60)
2.56(25)
2.37(<10)
1.68(20)
1.48(30)
_________(
(
Halloysite-10A (1)
(
10.1(90)
4.42(100)
3.34(90)
2.56(80)
1.68(80)
1.48(90)
1.28(70)
1.23(70)
________(
(
Halloysite-10A (2)
(
10.0(100)
4.36(70)
3.35(40)
2.54(35)
1.67(10)
1.48(30)
1.28(10)
(
(

Synonyms of HalloysiteHide

Other Language Names for HalloysiteHide

Varieties of HalloysiteHide

Chrome-HalloysiteA pale blue chromian Halloysite
Cuprian HalloysiteA cupriferous variety of halloysite
Ferrian HalloysiteAn Fe-rich variety of halloysite.
Zirconian HalloysiteHalloysite with content 3-4 wt.% ZrO2.

Relationship of Halloysite to other SpeciesHide

Other Members of this group:
DickiteAl2(Si2O5)(OH)4Mon. m : Bb
Greenalite(Fe2+,Fe3+)2-3Si2O5(OH)4Mon.
KaoliniteAl2(Si2O5)(OH)4Tric. 1 : P1
ManandoniteLi2Al4(Si2AlB)O10(OH)8Orth.
NacriteAl2(Si2O5)(OH)4Mon. m : Bb
Odinite(Fe,Mg,Al,Fe,Ti,Mn)2.4((Si,Al)2O5)(OH)4Mon. m : Bm
Serpentine SubgroupD3[Si2O5](OH)4 D= Mg, Fe, Ni, Mn, Al, Zn

Common AssociatesHide

Associated Minerals Based on Photo Data:
Atacamite68 photos of Halloysite associated with Atacamite on mindat.org.
Libethenite45 photos of Halloysite associated with Libethenite on mindat.org.
Pseudomalachite25 photos of Halloysite associated with Pseudomalachite on mindat.org.
Chrysocolla18 photos of Halloysite associated with Chrysocolla on mindat.org.
Adamite3 photos of Halloysite associated with Adamite on mindat.org.
Kornerupine2 photos of Halloysite associated with Kornerupine on mindat.org.
Mimetite2 photos of Halloysite associated with Mimetite on mindat.org.
Olivenite2 photos of Halloysite associated with Olivenite on mindat.org.
Chamosite2 photos of Halloysite associated with Chamosite on mindat.org.
Cerussite1 photo of Halloysite associated with Cerussite on mindat.org.

Related Minerals - Nickel-Strunz GroupingHide

9.ED.ClinochrysotileMon. 2/m
9.ED.05DickiteAl2(Si2O5)(OH)4Mon. m : Bb
9.ED.05KaoliniteAl2(Si2O5)(OH)4Tric. 1 : P1
9.ED.05NacriteAl2(Si2O5)(OH)4Mon. m : Bb
9.ED.05Odinite(Fe,Mg,Al,Fe,Ti,Mn)2.4((Si,Al)2O5)(OH)4Mon. m : Bm
9.ED.10HisingeriteFe3+2(Si2O5)(OH)4 · 2H2OMon.
9.ED.10Halloysite-7ÅAl2(Si2O5)(OH)4Mon. m : Bb
9.ED.15AmesiteMg2Al(AlSiO5)(OH)4Tric. 1 : P1
9.ED.15AntigoriteMg3(Si2O5)(OH)4Mon. m : Bm
9.ED.15Berthierine(Fe2+,Fe3+,Al)3(Si,Al)2O5(OH)4Mon. m : Bm
9.ED.15Brindleyite(Ni,Al)3(Si,Al)2O5(OH)4Mon.
9.ED.15CaryopiliteMn2+3Si2O5(OH)4Mon.
9.ED.15ChrysotileMg3(Si2O5)(OH)4Mon.
9.ED.15CronstedtiteFe2+2Fe3+((Si,Fe3+)2O5)(OH)4Trig. 3m : P3 1m
9.ED.15Fraipontite(Zn,Al)3((Si,Al)2O5)(OH)4Mon.
9.ED.15Greenalite(Fe2+,Fe3+)2-3Si2O5(OH)4Mon.
9.ED.15KellyiteMn2+2Al(AlSiO5)(OH)4Hex.
9.ED.15LizarditeMg3(Si2O5)(OH)4
9.ED.15ManandoniteLi2Al4(Si2AlB)O10(OH)8Orth.
9.ED.15Népouite(Ni,Mg)3(Si2O5)(OH)4Orth.
9.ED.15PecoraiteNi3(Si2O5)(OH)4Mon.
9.ED.15GuidottiiteMn2Fe3+(Fe3+SiO5)(OH)4Hex. 6 : P63
9.ED.20Allophane(Al2O3)(SiO2)1.3-2 · 2.5-3H2OAmor.
9.ED.20ChrysocollaCu2-xAlx(H2-xSi2O5)(OH)4 · nH2OOrth.
9.ED.20ImogoliteAl2SiO3(OH)4
9.ED.20Neotocite(Mn,Fe,Mg)SiO3 · H2OAmor.
9.ED.25BismutoferriteFe3+2Bi(SiO4)2(OH)Mon. m : Bm
9.ED.25ChapmaniteFe3+2Sb3+(Si2O5)O3(OH)Mon. m : Bm

Related Minerals - Dana Grouping (8th Ed.)Hide

71.1.1.1DickiteAl2(Si2O5)(OH)4Mon. m : Bb
71.1.1.5Odinite(Fe,Mg,Al,Fe,Ti,Mn)2.4((Si,Al)2O5)(OH)4Mon. m : Bm

Related Minerals - Hey's Chemical Index of Minerals GroupingHide

15.1AndalusiteAl2(SiO4)OOrth. mmm (2/m 2/m 2/m) : Pnnm
15.2KyaniteAl2(SiO4)OTric. 1 : P1
15.3SillimaniteAl2(SiO4)OOrth. mmm (2/m 2/m 2/m)
15.4MulliteAl4+2xSi2-2xO10-xOrth. mmm (2/m 2/m 2/m) : Pbam
15.5PyrophylliteAl2Si4O10(OH)2Tric. 1
15.6DickiteAl2(Si2O5)(OH)4Mon. m : Bb
15.7NacriteAl2(Si2O5)(OH)4Mon. m : Bb
15.8KaoliniteAl2(Si2O5)(OH)4Tric. 1 : P1
15.9MetahalloysiteAl2(Si2O5)(OH)4
15.11Allophane(Al2O3)(SiO2)1.3-2 · 2.5-3H2OAmor.

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.
Industrial Uses:
Used in applications similar to those of kaolinite, such as high-strength cements and high-quality ceramics.

Halloysite in petrologyHide

An essential component of rock names highlighted in red, an accessory component in rock names highlighted in green.

References for HalloysiteHide

Reference List:
Sort by Year (asc) | by Year (desc) | by Author (A-Z) | by Author (Z-A)
Clays and Clay Minerals (1978) 26: 25.
Gaines, R.V., Skinner, H.C.W., Foord, E.E., Mason, B., Rosenzweig, A. (1997) Dana's New Mineralogy: The System of Mineralogy of James Dwight Dana and Edward Salisbury Dana: 1411.
Burford, E.P., Kierans, M., Gadd, G.M. (2003): Geomycology: fungi in mineral substrata. Mycologist: 17(3): 98-107; DOI: 10.1017/S0269915X03003112
Joussein, E., Petit, S., Churchman, J., Theng, B., Righi, D., Delvaux, B. (2005) Halloysite clay minerals — A review. Clay Minerals: 40: 383–426.

Internet Links for HalloysiteHide

Localities for HalloysiteHide

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.

Locality ListShow

Mineral and/or Locality  
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