Halloysite Mineral Data

General Halloysite Information

Chemical Formula:

Al2Si2O5(OH)4

Composition:

Molecular Weight = 258.16 gm

Aluminum 20.90 % Al 39.50 % Al₂O₃

Silicon 21.76 % Si 46.55 % SiO₂

Hydrogen 1.56 % H 13.96 % H₂O

Oxygen 55.78 % O

______ ______

100.00 % 100.00 % = TOTAL OXIDE

Empirical Formula:

Al₂Si₂O₅(OH)₄

Environment:

A product of hydrothermal alteration or surface weathering of aluminosilicate minerals, as feldspars. Formed by dehydration of endellite above 110 deg. C.

IMA Status:

Valid Species (Pre-IMA) 1826

Locality:

Angleur, Liµege, Belgium. Link to MinDat.org Location Data.

Name Origin:

Named after Baron Omalius d'Halloy (1707-1789).

Name Pronunciation:

Halloysite + Pronunciation

Synonym:

Endellite

ICSD 26716

PDF 29-1489

halloysite-10 Ang.

Halloysite Image

Images:

Halloysite Pseudomalachite

Comments: Deep green pseudomalachite crystals on cuprous halloysite.
Location: Black Pine Mine, Philipsburg, Granite Co., Montana, USA. Scale: Crystal size 1-2 mm.
© John Veevaert

Images:

Halloysite

Comments: Pale tan sectile porcelaneous massive halloysite.
Location: Monroe County, Indiana, USA. Scale: See Photo.
© Jeff Weissman / Photographic Guide to Mineral Species

Halloysite Crystallography

Axial Ratios:

a:b:c =0.5775:1:1.6741

Cell Dimensions:

a = 5.14, b = 8.9, c = 14.9, Z = 4; beta = 101.9° V = 666.97 Den(Calc)= 2.57

Crystal System:

Monoclinic - DomaticH-M Symbol (m) Space Group: Cc

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

By Intensity(I/I_o): 10(1), 4.36(0.7), 3.35(0.4),2.54(0.35), 1.48(0.3), 1.672(0.14), 1.281(0.08),

Physical Properties of Halloysite

Cleavage:

None

Color:

White, Yellowish white, Reddish white, Brownish white, Greenish white.

Density:

2.55 - 2.65, Average = 2.59

Diaphaneity:

Translucent to opaque

Fracture:

Earthy - Dull, clay-like fractures with no visible crystalline affinities, (e.g. howlite).

Habit:

Earthy - Dull, clay-like texture with no visible crystalline affinities, (e.g. howlite).

Hardness:

2 - Gypsum

Luminescence:

Non-fluorescent.

Luster:

Earthy (Dull)

Streak:

white

Optical Properties of Halloysite

Gladstone-Dale:

CI meas= 0.043 (Good) - where the CI = (1-KPDmeas/KC)
CI calc= 0.031 (Excellent) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.2189,KPDmeas= 0.2164,KC= 0.226
Ncalc = 1.58 - 1.6

Optical Data:

Biaxial (?), a=1.553-1.565, b=1.559-1.569, g=1.56-1.57, bire=0.0050-0.0070

Calculated Properties of Halloysite

Electron Density:

Bulk Density (Electron Density)=2.59 gm/cc
note: Specific Gravity of Halloysite =2.57 gm/cc.

Fermion Index:

Fermion Index = 0.01
Boson Index = 0.99

Photoelectric:

PE_Halloysite= 1.48 barns/electron
U=PE_Halloysite x rElectron Density= 3.83 barns/cc.

Radioactivity:

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

Halloysite Classification

Dana Class:

71.01.01.04 (71)Phyllosilicate Sheets of Six-Membered Rings

(71.01)with 1:1 layers

(71.01.01)Kaolinite group

71.01.01.01 Dickite Al2Si2O5(OH)4 Cc m

71.01.01.02 Kaolinite Al2Si2O5(OH)4 P1 1

71.01.01.03 Nacrite Al2Si2O5(OH)4 Cc m

71.01.01.04 Halloysite Al2Si2O5(OH)4 Cc m

71.01.01.04a Endellite? Al2Si2O5(OH)4•2(H2O) Cc m

71.01.01.05 Odinite (Fe,Mg,Al,Fe,Ti,Mn)2.5(Si,Al)2O5(OH)4 Cm m

Strunz Class:

09.ED.10 09 - SILICATES (Germanates)

09.E - Phyllosilicates

09.ED -Phyllosilicates with kaolinite layers

09.ED.10 Endellite! Al2Si2O5(OH)4•2(H2O) Cc m

09.ED.10 Hisingerite Fe2Si2O5(OH)4•2(H2O) Unk Mono

09.ED.10 Halloysite Al2Si2O5(OH)4 Cc m

09.ED.10 Sturtite? (Fe3)(Mn2,Ca,Mg)Si4O10(OH)3•10(H2O) None

Other Halloysite Information

References:

NAME( AntBidBlaNic2) PHYS. PROP.(AntBidBlaNic2) OPTIC PROP.(Mason68)

See Also:

Links to other databases for Halloysite :
1 - Am. Min. Crystal Structure Database
2 - Athena
3 - EUROmin Project
4 - Ecole des Mines de Paris
5 - Franklin Minerals(Palache)
6 - GeoScienceWorld
7 - Google Images
8 - Google Scholar
9 - Handbook of Mineralogy (MinSocAm)
10 - Handbook of Mineralogy (UofA)
11 - MinDAT
12 - Mineralienatlas (Deutsch)
13 - NSDL Reciprocal Net (JAVA)
14 - Online Mineral Museum
15 - QUT Mineral Atlas
16 - Ruff.Info
17 - Scandinavian mineral gallery

Search for Halloysite using:

[AOL] [Bing] [Dog Pile] [GeoScienceWorld] [HotBot] [Ixquick] [Lycos] [MAMMA] [Scirus] [Teoma] [WebCrawler] [Wikipedia] [YAHOO]

Visit our Advertisers for Halloysite :

A Bijoux Google Search for Halloysite
Adam's Minerals Google Search for Halloysite
Cape Minerals Google Search for Halloysite
Dakota Matrix Minerals Google Search for Halloysite
Excalibur Mineral Corp. Google Search for Halloysite
Exceptional Minerals Google Search for Halloysite
John Betts Fine Minerals Search for Halloysite
McDougall Minerals Google Search for Halloysite
Mineral News Website Link
Rock and Mineral Shows Google Search for Halloysite
Weinrich Minerals, Inc. Google Search for Halloysite

Ask about Halloysite here :
Ask-A-Mineralogist from the Mineralogical Society of America
Mindat.org's Discussion Groups
Original Rockhounds Discussion Group
Rockhounds Discussion Group on Yahoo Groups
Mineral Discussion Forum from Fabre Minerals - also available in Español

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

Halloysite

Al2Si2O5(OH)4
Dana No: 71.01.01.04 Strunz No: 09.ED.10
Locality:

Notes: