Understanding the ancient geomagnetic fields recorded in rocks provides insights into the Earth's geological evolution. When cooling down, magnetic minerals acquire a thermoremanent magnetization that can be analyzed in the laboratory to reconstruct past magnetic fields. However, some rocks can also experience chemical alteration that can induce an additional chemical remanent magnetization. This secondary magnetization complicates the interpretation of paleomagnetic signals. Furthermore, current theoretical models rely on uniformly magnetized particles, but most magnetic mineral particles in nature exhibit non-uniform magnetic structures. Here we use advanced micromagnetic modeling to study how non-uniformly magnetized particles acquire chemical remanent magnetization during grain growth. Our findings reveal that these particles can still faithfully record paleomagnetic information, providing new insights into the complexities of chemical remanent magnetization acquisition and its implications for interpreting Earth's magnetic history.