Abstract This review focuses on bacteria and their role in mineral formation. As a consequence of their small size and diverse metabolic capabilities bacteria, more than any other type of living organism, are able to interact intimately with metal ions present in their environment. Some metals are required for metabolism and are taken into the cell through various mechanisms, then incorporated into the necessary physiological pathways and biosynthetic structures. This physiological aspect of metal-bacterial interaction will not be discussed but, rather, the ability of bacteria to accumulate metal ions and incorporate them into mineral phases will be described. This activity has widespread importance for the shaping of our planet and the recycling of mineral elements. Since bacteria are most frequently found as part of microbial communities it is within this context that their mineral-forming ability will be discussed.