Kaolin or Kaolinite Composition, Crystallization & Structure
Composition. An aluminum silicate, H4AL2Si209 = Silica 46.5, alumina 39.5, water 14.
Crystallization. Monoclinic. In very minute, thin, rhombi or hexagonal-shaped plates.
Structure. Usually in claylike masses, either compact or friable.
Physical Properties. Perfeet basal cleavage. H. = 2-2.5. G. = 2.6-2.63. Luster usually dull earthy; crystals plates pearly. Color white. Often variously colored by impurities. Usually unctuous and plastic.
Tests. Infusible. Insoluble. Assumes a blue color when moistened with cobalt nitrate and ignited (aluminum). Recognized usually by its claylike character.
Occurrence. Of widespread occurrence. The chief constituent of clay. Always a mineral of secondary origin, being derived by the alteration of aluminum silicates, particularly feldspar. It is found mixed with feldspar in rocks that are undergoing alteration; at times it forms entire beds where such alteration has been carried to completion. As one of the common products of the decomposition of rocks it gets into soils and being transported by water is deposited, mixed with quartz and other materials in lakes, etc., in the form of beds of clay.
Name. Kaolin is a corruption of the Chinese, Kauling, a locality from which material was obtained for the manufacture of porcelain and which was thought to be the same as kaolin.
Use. Used in the form of clay in making all kinds of pottery, stoneware, bricks, etc. The finer, purer grades of kaolin are used in the manufacture of porcelain, china, etc.
Oxides of the Semimetals and Metals Metasilicates – Leucite Composition, Crystallization & Structure Services Required in a Mining Operation Hydrocone' Reduction Crusher Grinding Efficiency Factors Chemical Mineralogy and Groups Capacity of Hammermills Identifying Lead Minerals How to Operate a Portland Cement Plant Health and Safety in Mining Stage- Crushing VS Closed-Circuit Crushing Orthosilicates – Nephelite Composition, Crystallization & Structure Identifying Antimony Minerals Reference on Sphalerite Activation Chlorides - Anhydrous Chlorides, the Halite Group
