Researchers at Graz University of Technology (TU Graz) created a new method to precisely determine the 3D distribution of foreign atoms in advanced porous materials. The unique approach also enabled them to uncover the underlying mystery surrounding the blue color of aquamarine minerals. Crystalline and nanoporous materials, often used in sensor and separation technologies, usually owe their defining properties to the presence of foreign-atoms nestled within the intricate lattice of their structure.