Аннотация:Modern society uses clays in an ever increasing quantity,making this category of minerals the most important industrialminerals for the future, being exploited for very wide varieties ofindustrial applications (agriculture, engineering, construction,geology, environment, and miscellaneous applications). The physicaland chemical properties of kaolin determine its use as an industrialmineral. Deposits can be sedimentary, residual, or hydrothermal andthe kaolin has different properties and thus must be fully tested andevaluated to determine its utilization. The aim of study is tocharacterize mineralogically the most important Portuguese kaolindeposits occurring in the NW of Portugal: Alvarães, Barqueiros andVila Fria), of sedimentary and residual origin.http://www.lneg.pt/iedt/unidades/16/paginas/26/30/185