The black heart corresponds to a dark nucleus formed in the central portion of ceramic pieces, due to the presence of iron and the incomplete combustion of organic matter that accompanies some clays. The objective of the analysis is to evaluate the tendency for black heart formation in samples of clay and ceramic bodies. The analyses are carried out on pressed and burned specimens under severe conditions to enhance the formation of black hearts. This is a comparative analysis that can be used to evaluate the potential of raw materials for the ceramic industry and can eventually guide the development of dough formulations and the optimization of processing conditions.