Keywords: classical crystal growth; nano X-ray computed tomography; reversed crystal growth; zeolite AST; zeolite crystallization EN classical crystal growth nano X-ray computed tomography reversed crystal growth zeolite AST zeolite crystallization 1 1 1 06/24/22 20220621 NES 220621 B A truly reversed crystal growth mode b in which the crystallization starts at the surface of a spherically amorphous aggregate and then proceeds towards its center is described. Classical crystal growth, nano X-ray computed tomography, reversed crystal growth, zeolite AST, zeolite crystallization.