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|System:||Triclinic||Colour:||White to cream and ...|
|Hardness:||2 - 2½|
|Name:||Named for the ancient Chinese type 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 whitish, pale yellow to light brown color.
See also the chemically identical halloysite-7Å.
Classification of Kaolinite
|IMA status:||Valid - first described prior to 1959 (pre-IMA) - "Grandfathered"|
|Explanation of status:||Officially "re-described" by Keller et al. (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:||18.104.22.168|
|Hey's CIM Ref.:||15.8|
15 : Silicates of Aluminum
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Type Occurrence of Kaolinite
|Type Locality:||Gaoling Mine (Kauling Mine), Gaoling village, Ehu town, Fuliang Co., Jingdezhen Prefecture, Jiangxi Province, China|
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|
|Density (calculated):||2.63 g/cm3|
Crystallography of Kaolinite
|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 Å³ (Calculated from Unit Cell)|
|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:|
|Comments:||Several polytypes known: -1Md, -2M^1 ("dickite"), -2M^2 ("nacrite"). Each has a slightly different powder pattern.|
Optical Data of Kaolinite
|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.
Chemical Properties of Kaolinite
|Simplified for copy/paste:||Al2(Si2O5)(OH)4|
|Essential elements:||Al, H, O, Si|
|All elements listed in formula:||Al, H, O, Si|
Relationship of Kaolinite to other Species
|Member of:||Serpentine Group|
|Other Members of Group:|
|Related Minerals - Nickel-Strunz Grouping):|
|Related Minerals - Hey's Index Grouping:|
|Related Minerals - Dana Grouping):|
Other Names for Kaolinite
|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
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
Localities for Kaolinite
The 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.