geochemistry

Geochemistry is the chemistry of the Earth's crust and oceans. The principles developed can be applied (perhaps with some generalization) to other planets (including extra-solar planets) and moons. Included are processes including the formation of the compounds that make up rocks, which are largely oxides (compounds with oxygen, primarily silica), chlorides (with chlorine), sulfides (with sulfur), and fluorides (with fluorine).