Difference between revisions of "Kaolinite"
Jump to navigation
Jump to search
| Line 1: | Line 1: | ||
[[File:B1216.jpg|thumb|Kaolin lion head from horse harness<br> MFA # 98.694]] | [[File:B1216.jpg|thumb|Kaolin lion head from horse harness<br> MFA # 98.694]] | ||
| + | [[File:Thomas Davies Pottery 2011.1807.jpg|thumb|Face jug<br>MFA #: 2011.1807]] | ||
| + | == Description == | ||
[[File:Kaoliniteemr1.jpg|thumb|Kaolinite]] | [[File:Kaoliniteemr1.jpg|thumb|Kaolinite]] | ||
| − | |||
| − | |||
A hydrated aluminum silicate mineral which is the principal constituent of [[kaolin]] clay. Kaolinite crystals have a lamellar or plate-like structure that gives the clay its slippery feel. It is a natural alteration product of aluminum silicate rocks, such as [[feldspar]]. Pure kaolinite is a primary [[clay]]. Most secondary clays contain only a small percentage of kaolinite (Fournier 1996). One exception is [[ball clay]] found in Wareham, England. | A hydrated aluminum silicate mineral which is the principal constituent of [[kaolin]] clay. Kaolinite crystals have a lamellar or plate-like structure that gives the clay its slippery feel. It is a natural alteration product of aluminum silicate rocks, such as [[feldspar]]. Pure kaolinite is a primary [[clay]]. Most secondary clays contain only a small percentage of kaolinite (Fournier 1996). One exception is [[ball clay]] found in Wareham, England. | ||
Revision as of 12:39, 12 March 2025
Description
A hydrated aluminum silicate mineral which is the principal constituent of Kaolin clay. Kaolinite crystals have a lamellar or plate-like structure that gives the clay its slippery feel. It is a natural alteration product of aluminum silicate rocks, such as Feldspar. Pure kaolinite is a primary Clay. Most secondary clays contain only a small percentage of kaolinite (Fournier 1996). One exception is Ball clay found in Wareham, England.
Synonyms and Related Terms
china clay, kaolin; gaoling (Chin.); Kaolinit (Deut.); caolinita (Esp.); kaolinite (Fr.); kaolien (Ned.); kaoliniet (Ned.); caulinite (Port.);
Risks
- Noncombustible.
- ThermoFisher: SDS
Physical and Chemical Properties
- Composition = Al2Si2O5(OH4)
- Mohs Hardness = 2.0 - 2.5
- Density = 2.6-2.63 g/ml
- Refractive Index = 1.558; 1.565; 1.564
- Insoluble in water, cold acids and alkalis.
- Monoclinic system with with hexagonal, plate-like crystals 0.1-1.0 micrometers.
- Perfect cleavage in one direction.
- Plastic when wet. Brittle when dry.
- Fracture = earthy (friable).
- Luster =dull to pearly.
- Streak = white
Resources and Citations
- WebMinerals: Kaolinite
- R. Fournier, Illustrated Dictionary of Practical Pottery, Chilton Book Co., Radnor, PA, 1996.
- Mineralogy Database: Kaolinite
- Encyclopedia Britannica, http://www.britannica.com Comment: "kaolinite" [Accessed December 4, 2001].
- Art and Architecture Thesaurus Online, http://www.getty.edu/research/tools/vocabulary/aat/, J. Paul Getty Trust, Los Angeles, 2000
- C.W.Chesterman, K.E.Lowe, Audubon Society Field Guide to North American Rocks and Minerals, Alfred A. Knopf, New York, 1979
- Wikipedia: Kaolinite (Accessed Sept. 7, 2005 and March 2025)
- R. J. Gettens, G.L. Stout, Painting Materials, A Short Encyclopaedia, Dover Publications, New York, 1966