It is a wordplay between “Petra” that means stone in Greek, and “Gaia” referring to the well-known theory in which planet Earth is presented with a holistic sense, in which it is considered to be a complex interaction between the biosphere, atmosphere, oceans, soils and rocks. Give place to the so-called Mother Earth, to whom we as professionals of the earth sciences owe the meaning of our profession. A simple tribute to her.