We revealed how transition metal phosphates form crystals through a non-classical pathway that involves temporary, amorphous particles on the way to the final crystal. These amorphous phases undergo various stages of aggregation, densification, and reconfiguration to proto-crystalline precursors varying considerably depending on the transition metal(s) involved. The reaction kinetics of the precipitation of TMP phases is primarily dependent on the involved transition metal(s), the stability properties of the amorphous precursors and their agglomerated entities. Additionally, the rate of formation is affected by the complexity of the final crystalline structure (layered vs. isolated structure). When combining Ni and Co equally in high concentration, the time it took to reach equilibrium was significantly prolonged, from a few minutes to several hours, providing evidence of the intricate interaction between transition metal ions and potential complexes, and the nucleating solid entities.