There is growing interest in the use of natural materials as alternatives to medicinal products composed of chemicals. For this reason, it is important to study materials which fill this need (e.g. the formulation of peloids). Historically, the Azores archipelago has long been visited for its mud baths, mainly on São Miguel Island, where volcanic muds demonstrate beneficial properties. The volcanic muds are scarce, however. Thus, residual clay materials of Santa Maria Island were studied to assess their suitability for the formulation of peloids. The results of tests from 20 samples, collected from all over the island, presented evidence that they are very favourable for peloid formulations, due to their mineralogical, chemical and technological properties. The materials showed good potential for blending with the São Miguel volcanic muds. The deposits studied show extensive outcrops.
