Biomineralization is a widespread and diverse process that is demonstrated by 64 known minerals that are produced by organisms from all eukaryotic clasters. That is why it is an area of interest and numerous researches are aimed at revealing the details of this process. Despite all the information we know today, we still have no real picture of how organisms produce minerals. However, we know a lot about how they control mineral formation and that is what makes biologically controlled mineralization. We have to keep in mind that the divisions created so far are used to make it easier for us to understand the biomineralization process and that in reality divisions are not so clear. Biomineralization occurs on such level that it strongly affects biosphere, such as ocean chemistry or composition of sedimentary rocks. In this paper, bivalves are thoroughly discussed because they are used for commercial purposes and also for the production of pearls. Besides bivalves, echinoderms are also well known biomineralists due to specific structures that they form and are therefore covered in this paper.