- It has been suggested that gastroliths are a good model for the study of biomineralization and extracellular organic matrix assembly, since they can serve as simplified cases of more complex mineralized biological structures, such as cuticles, bone, and teeth. Proteins are known to be key players in biomineralized chitinous matrices in general and in gastrolith assembly in particular. Here, we present a structural model that is based on the integration into the gastrolith assembly of the gastrolith proteins identified thus far. The model allows the assignment of these proteins to the different aspects of gastrolith construction, based on their characteristics. The model also predicts the existence of several additional proteins yet to be identified.