Looking for traces of life in minerals

Traces of life have been extensively looked for in minerals. It is indeed thought that a wide diversity of living organisms can control the formation of mineral phases and thus may leave imprints of their activity in the morphology, chemistry and crystallographic structure of the mineral end-product. Here, we illustrate the bases and limits of this approach by reviewing some studies on biogenic magnetites and carbonates. More than an exhaustive review, we give a personal view on the limitations provided by an empirical approach based on defining so-called biosignatures and suggest developing a more comprehensive mechanistic understanding of how life controls mineral nucleation and growth and induces potential specific features.