The aim of the teaching is to provide the basic knowledge on chemico-physical and thermodynamic laws that govern solid-melt-gas phase equilibria and reactivity of Earth materials. Major topics are: i) geochemistry and thermodynamics of crystalline solids (pure solids and solid mixtures); ii) geochemistry of silicate melts and glasses; iii) phase diagrams of petrogenetic interest; iv) geochemistry of aqueous solutions (e.g. Eh-pH and activity diagrams); v) geochemistry of gaseous phases; vi) basic concepts of cosmochemistry and isotopic geochemistry (e.g. age of the Earth, meteorites). Some lectures, tutorials and practice on computational modelling in geochemistry are also included in the course.