Organisms can precipitate a wide array of minerals which they use to build calcified tissues (i.e., bone, mollusk shell, eggshell, coccolith) having highly sophisticated microstructures. The disposition of organic and mineral components building these materials is highly organized from the nano- to the millimeter scale. Their ordered assembly implies self-organization processes accorded in space and time, giving rise to highly sophisticated textured materials. The objective of our work is the study of fundamental processes in biomineralization such as self-organization processes and texture control in biomineral crystal aggregates. To study the order in the arrangement of shell making crystals we used area detectors available today in modern X-ray diffractometers. The 2D diffraction patterns, collected using such detectors, contain detailed information not only about the mineralogy but also about the microstructure characteristics of polycrystalline materials – crystal size, stress, crystallinity and crystallographic-texture. For instance, to understand microstructure development in mollusk shells, we use this type of detector to do microdiffraction analyses combined with high resolution SEM in order to follow the ordering mechanisms of crystals making these biomaterials.