Coatings occur along interfaces between rocks and minerals and their environment. Coatings result from the wide variety of reactions and/or processes that occur at the interface between the lithosphere and the biosphere, hydrosphere, and atmosphere. Such coatings are biochemically, mineralogically and isotopically complex and have the potential to record changes in their immediate environment. The transition between a coating and its underlying host is abrupt and defined by a sharp interface at the nanoscale. Articles in this issue highlight new and exciting research in the field of coatings, focussing on coatings formed in deserts, soils, sediments, oceans, and on rocks from Mars.