The scientific study of the chemistry of the Earth, including the rocks, sediments, and soil that constitute the solid Earth and the fluids that compose the ocean, inland waters, and the atmosphere: Geochemistry refers to chemical reactions involving Earth materials, such as soil, rocks, and water.

Geochemistry is the chemistry of the composition and alterations of the solid matter of the Earth or of a celestial body.

The study of the chemistry of the Earth includes the study of the rocks and sediments that constitute the solid Earth, as well as the fluids of the oceans, inland waters, and the atmosphere.

Geochemistry is based on a foundation of other sciences, including chemistry, geology, physics, and biology. This field of research concentrates on the movement, or flux, of chemical elements through the solids and fluids of the Earth.