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Kaolinite

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McMichael Mine, Andersonville, Macon Co., Georgia, USA
© Charles Creekmur

Show Kaolinite Photos (25)
Formula:
Al
 
2
Si
 
2
O
 
5
(OH)
 
4
System:TriclinicColour:White to cream and ...
Hardness:2 - 2½
Name:Named for the ancient Chinese locality "Kaoling (Gaoling)", meaning high ridge.


Kaolinite was known since the Yuan (Mongol) dynasty in the thirteenth century as "Kaolin earth" and was first properly described by Song Yingxing in the early seventeenth century in his book Tian Gong Kai Wu (roughly: Introduction to Heaven's Handicrafts). It was introduced to the West by a French priest in 1712 (de Fourestier, 2005).

Found largely in masses - clay beds - with a light brown color.

Classification of Kaolinite

IMA status:Approved 1980
Strunz 8th edition ID:8/H.25-10
Nickel-Strunz 10th (pending) edition ID:9.ED.05

9 : SILICATES (Germanates)
E : Phyllosilicates
D : Phyllosilicates with kaolinite layers composed of tetrahedral and octahedral nets
Dana 7th edition ID:71.1.1.2
Hey's CIM Ref.:15.8

15 : Silicates of Aluminum
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Type Occurrence of Kaolinite

Type Locality:Morro do Felipe, Boca do Jari District, Mazagão, Amapá, North Region, Brazil

Occurrences of Kaolinite

Geological Setting:A primary constiuent of clay beds formed by the decomposition of feldspar-bearing rocks.

Physical Properties of Kaolinite

Lustre:Waxy, Pearly, Dull, Earthy
Diaphaneity (Transparency):Translucent, Opaque
Colour:White to cream and pale-yellow, also often stained various hues, tans and browns being common.
Streak:White, or paler than the sample.
Hardness (Mohs):2 - 2½
Hardness Data:Measured
Tenacity:Sectile
Cleavage:Perfect
on {001}.
Fracture:Sub-Conchoidal
Density (calculated):2.63 g/cm3

Crystallography of Kaolinite

Crystal System:Triclinic
Class (H-M):1 - Pedial
Cell Parameters:a = 5.13Å, b = 8.89Å, c = 7.25Å
α = 90°, β = 104.5°, γ = 89.8°
Ratio:a:b:c = 0.577 : 1 : 0.816
Unit Cell Volume:V 320.11 ų (Calculated from Unit Cell)
Z:1
Morphology:Visible crystals extremely rare, typically 2-5 nanometer range, but may be up to 1 mm across. Platy, pseudohexagonal. Fibers and spheres have been observed using SEM imaging.
X-Ray Powder Diffraction:
d-spacingIntensity
For kaolinite-1A:(
(
7.17(100)
4.37(60)
4.19(45)
3.58(80)
1.62(70)
1.59(60)
Comments:Several polytypes known: -1Md, -2M^1 ("dickite"), -2M^2 ("nacrite"). Each has a different powder pattern.

Optical Data of Kaolinite

Type:Biaxial (-)
RI values: nα = 1.553 - 1.563 nβ = 1.559 - 1.569 nγ = 1.560 - 1.570
2V:Measured: 24° to 50°, Calculated: 44°
Maximum Birefringence:δ = 0.007

Chart shows birefringence interference colour range (at 30µm thickness) and does not take into account mineral colouration.
Surface Relief:Low
Dispersion:none

Chemical Properties of Kaolinite

Formula:
Al
 
2
Si
 
2
O
 
5
(OH)
 
4
Essential elements:Al, H, O, Si
All elements listed in formula:Al, H, O, Si
Common Impurities:Fe,Mg,Na,K,Ti,Ca,H2O

Relationship of Kaolinite to other Species

Member of:Serpentine Group
Related Minerals - Nickel-Strunz Grouping):
9.ED.05Dickite
Al
 
2
Si
 
2
O
 
5
(OH)
 
4
9.ED.05Nacrite
Al
 
2
Si
 
2
O
 
5
(OH)
 
4
9.ED.05Odinite
(Fe,Mg,Al,Fe,Ti,Mn)
 
2.4
(Si,Al)
 
2
O
 
5
(OH)
 
4
9.ED.10Halloysite
Al
 
2
Si
 
2
O
 
5
(OH)
 
4
9.ED.10Hisingerite
Fe
3+
2
Si
 
2
O
 
5
(OH)
 
4
·2H
 
2
O
9.ED.10Halloysite-7Å
Al
 
2
Si
 
2
O
 
5
(OH)
 
4
9.ED.10Halloysite-10Å
Al
 
2
Si
 
2
O
 
5
(OH)
 
4
·2H
 
2
O
9.ED.15Amesite
Mg
 
2
Al[(OH)
 
4
|AlSiO
 
5
]
9.ED.15Antigorite
(Mg,Fe
2+
 
)
 
3
[(OH)
 
4
|Si
 
2
O
 
5
]
9.ED.15Berthierine
(Fe,Fe,Mg)
 
2-3
(Si,Al)
 
2
O
 
5
(OH)
 
4
9.ED.15Brindleyite
(Ni,Mg,Fe)
 
2
Al(Si,Al)O
 
5
(OH)
 
4
9.ED.15Caryopilite
(Mn,Mg)
 
3
Si
 
2
O
 
5
(OH)
 
4
9.ED.15Chrysotile
Mg
 
3
Si
 
2
O
 
5
(OH)
 
4
9.ED.15Cronstedtite
Fe
2+
2
Fe
3+
 
[(Si,Fe
3+
 
)
 
2
O
 
5
](OH)
 
4
9.ED.15Fraipontite
(Zn,Al)
 
3
[(OH)
 
4
|(Si,Al)
 
2
O
 
5
]
9.ED.15Greenalite
Fe
 
2-3
Si
 
2
O
 
5
(OH)
 
4
9.ED.15Kellyite
Mn
2+
2
Al[(OH)
 
4
|AlSiO
 
5
]
9.ED.15Lizardite
Mg
 
3
[(OH)
 
4
|Si
 
2
O
 
5
]
9.ED.15Manandonite
LiAl
 
4
Si
 
3
BO
 
10
(OH)
 
6
9.ED.15Népouite
(Ni,Mg)
 
3
Si
 
2
O
 
5
(OH)
 
4
9.ED.15Pecoraite
Ni
 
3
[(OH)
 
4
|Si
 
2
O
 
5
]
9.ED.20Allophane
(Al
 
2
O
 
3
)(SiO
 
2
)
 
1.3-2
·2.5-3H
 
2
O
9.ED.20Chrysocolla
(Cu,Al)
 
2
H
 
2
Si
 
2
O
 
5
(OH)
 
4
·nH
 
2
O
9.ED.20Imogolite
Al
 
2
SiO
 
3
(OH)
 
4
9.ED.20Neotocite
(Mn,Fe,Mg)SiO
 
3
·H
 
2
O
9.ED.25Bismutoferrite
Fe
3+
2
Bi[OH|(SiO
 
4
)
 
2
]
9.ED.25Chapmanite
Fe
3+
2
Sb
3+
 
[OH|(SiO
 
4
)
 
2
]
Related Minerals - Hey's Index Grouping:
15.1Andalusite
Al
 
2
[O|SiO
 
4
]
15.2Kyanite
Al
 
2
[O|SiO
 
4
]
15.3Sillimanite
Al
 
2
[O|SiO
 
4
]
15.4Mullite
Al
 
8
[(O,OH,F)|(Si,Al)O
 
4
]
 
4
15.5Pyrophyllite
Al
 
2
Si
 
4
O
 
10
(OH)
 
2
15.6Dickite
Al
 
2
Si
 
2
O
 
5
(OH)
 
4
15.7Nacrite
Al
 
2
Si
 
2
O
 
5
(OH)
 
4
15.9Metahalloysite
Al
 
2
Si
 
2
O
 
5
(OH)
 
4
15.10Halloysite
Al
 
2
Si
 
2
O
 
5
(OH)
 
4
15.11Allophane
(Al
 
2
O
 
3
)(SiO
 
2
)
 
1.3-2
·2.5-3H
 
2
O
Related Minerals - Dana Grouping):
71.1.1.1Dickite
Al
 
2
Si
 
2
O
 
5
(OH)
 
4
71.1.1.3Nacrite
Al
 
2
Si
 
2
O
 
5
(OH)
 
4
71.1.1.4Halloysite
Al
 
2
Si
 
2
O
 
5
(OH)
 
4

Other Names for Kaolinite

Synonyms:
AncuditeCarnatChina ClayClayite (of Mellor)Cleîte
CollyrinumCollyrumCreniaditeFireclayKaolin
LeucargillaMarga PorcellanaMyelinNeokaolinPholerite
Porcelain ClayPorcelain EarthPorzellanerde
German names:
AncuditCleîtCreniaditKaolinitPholerit
Italian names:
Caolinite
Japanese names:
カオリナイト
Russian names:
Каолинит
Spanish names:
AncuditaCleîtaCreniaditaKaolinita
Varieties:
Chrome-KaoliniteChrome-KaolinteKeramite (of Hunt)Parakaolinite

Other Information

Health Warning:No information on health risks for this material has been entered into the database. You should always treat mineral specimens with care.
Industrial Uses:Numerous: fillers and coatings in/on papers, for making china and various other earthenware items, an absorbant in dye tracers, a pore-forming enhancer for dye uptake in inks, as an absobant for spills, as a stain preventing coating on lithographic plate

References for Kaolinite

Reference List:Ross, Clarence Samuel & Paul F. Kerr (1930), The kaolin minerals. USGS Professional Paper 165-E: 151-176.

Brindley, G.W. and Nakahira, M. (1959) The kaolinite-mullite reaction series: I, Survey of outstanding problems. II, Metakaolin. III, The high-temperature phases. Journal of the American Ceramic Society: 42: 311-324.

Conti L., Traversa G. (1968) - Caolinite ottenuta per trasformazione idrotermale della biotite. Periodico di mineralogia –Roma, pp. 605-624.

Bailey, S.W. & R.B. Langston (1969), Anauxite and kaolinite structure identical: Clays and Clay Minerals: 17: 241-243.

Langston, R.B. & J.A. Pask (1969), The nature of anauxite: Clays and Clay Minerals: 16: 425-436.

Leonard, A.J. (1977) Structural analysis of the transition phases in the kaolinite-mullite thermal sequence ournal of the American Ceramic Society: 60: 37-43.

Keller, W.D., Hsia Cheng, Johns, W.D., and Chi-Sheng Meng (1980): Kaolin from the original Kauling (Gaoling) Mine locality, Kiangsi Province, China. Clays and Clay Minerals 28(2), 97-104.

May, H.M., D.G. Kinniburgh, P.A. Helmke, and M.L. Jackson (1986), Aqueous dissolution, solubilities and thermodynamic stabilities of common alumino-siolicate cla minerals; kaolinite and smectite. Geochimica et Cosmochimica Acta: 50: 1667-1677.

Srikrisna, K., Thomas, G., Martinez, R., Corral, M.P., de Aza, S., and Moya, J.S. (1990) Kaolinite-mullite reaction series: a TEM study. Journal of Materials Science: 25: 607-612.

Clays and Clay Minerals (1993): 41: 738.

Gaines, Richard V., H. Catherine, W. Skinner, Eugene E. Foord, Brian Mason, Abraham Rosenzweig (1997), Dana's New Mineralogy : The System of Mineralogy of James Dwight Dana and Edward Salisbury Dana: 1407.

Lee, S., Kim, Y.J., and Moon, H.S. (1999) Phase transformation sequence from kaolinite to mullite investigated by an energy-filtering transmission electron microscope. Journal of the American Ceramic Society: 82: 2841-2848.

Farmer, V.C. (2000) Transverse and longitudinal crystal modes associated with OH stretching vibrations in single crystals of kaolinite and dickite. Spectrochimica Acta: A56: 927-930.

Frost, R.L., Fredericks, P.M., Kloprogge, J.T., and Hope, G.A. (2001) Raman spectroscopy of kaolinites using different excitation wavelengths. Journal of Raman Spectroscopy: 32: 657-663.

Internet Links for Kaolinite

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    Localities for Kaolinite

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