The Jurassic kaolinite-illite clays in Rozwady (Opoczno region) were exploited for the needs of the chamotte fireclay refractories plant in Opoczno built in the years 1926–1928. Until the World War II, these clays were a major component of ceramic sets used for manufacturing quartz-chamotte refractories applicable to steel-making ladles in the Upper Silesian steel works. In the year 1990, due to a drastically low demand for chamotte refractories in Poland, both the plant in Opoczno and the Mroczków-Rozwady clay underground mine were shut down. However, recent years have brought about a renewed interest in exploiting the Opoczno clays for the domestic ceramic industry. Clay mining was initiated in 2014 in the new open pit in Borkowice and has also continued as of 2017 exploiting the Rozwady I deposit. In the clay raw material of Rozwady, kaolinite clearly predominates over illite, among the non-clay minerals quartz occurs in variable quantities, whereas the organic matter is a permanent but minor component. The quantity of the organic matter varies within the deposit and forms the basis to distinguish light and dark colored clays. Considering the petrographical reasons, the raw material of Rozwady represents rocks intermediate between claystones and mudstones. The Rozwady clays have been used by many plants producing tiles within the Opoczno region and it is predicted that their use will increase, as the prices of the clay raw materials imported from Ukraine is constantly growing and the cost of their transport is substantial.