The special clays, black and gray, occur in the Pliocenic sedimentary basin of the Leiria - Pombal region.
In the Barracão ore are exploited plastic clays that show chemical and mineralogical parameters suited for their application in the unglazed porcelain floor and wall tiles porcelain.
In the Redinha ore (Pombal) are exploited polychromatic clays with post-cooking parameters which enable their application in the sectors of ceramic wall tiles and unglazed porcelain floor and wall tiles (Fig.5).
In the Plio-Quaternary formations of the Anadia region (Monsarros ore) are extracted special clays suited for application in the segments ceramic products for mono and bi-cooking.
The kaolins are the result of industrial washing of detrital lithological units exploited in the Grés Belasianos Sedimentary Sequence (Lower Cretaceous) of the Albergaria dos Doze region (Pombal).
The red clays, with application in structural ceramics, particularly in the rooftop and porcelain floor tiles, are exploited in the Upper layers of the Vale de Lagares Complex (Upper Jurassic.) and Plio-Quaternary formations of the Anadia region.
To maintain a quality control over the raw materials extracted at the exploration centers and over the clay mixtures, the Argilis, Ltd. owns a laboratory devoted and prepared for the determination of physical parameters of the clays, in fresh and after cooking.