Core/double-shell nanoparticles are produced by solid-state precipitation in an aluminum matrix and characterized by transmission electron microscopy and atom-probe tomography. By choosing three solute elements (Yb, Sc, Li) with substantially disparate diffusivities and by judiciously selecting aging temperatures to precipitate each element sequentially, nanoparticles are formed with three chemically distinct concentric Al3(Yb,Sc,Li) phases with radii of 1.6, 3.4, and 13.4 nm.