Morphological evolution of precipitates during transformation of amorphous calcium phosphate into octacalcium phosphate in relation to role of intermediate phase

► Transformation of ACP into OCP was investigated focusing on precipitates' morphology. ► ACP spherulites transformed into OCP single crystal without dissolution. ► Initial morphology of ACP remained unchanged during transformation to OCP. ► OCP was the pseudomorph of ACP. ► Pseudo β-TCP appeared as an intermediate phase during transformation.