El deposito de caolin de Cazalla de La Sierra, Sevilla (Espana).

The kaolin deposit of Cazalla de La Sierra (Sevilla) was formed by supergenic alteration of cataclastic rocks (aplites) of the Campoallà Formation (Lower Cambrian, Ossa-Morena Zone). The percentage 44 micrometers fraction in the raw materials is not higher than 50 wt%. The major mineral composition consists of halloysite, kaolinite, feldspars and quartz; smectite and illite occur as minor components. The genetic controls of this deposit are the aplitic nature of the parent rocks and its strong fracturing, therefore the kaolinization is restricted to a limited area. At present this deposit does not offer any economical interest because of its small dimension and vertical variable quality.