Abstract: Ruggedized luminescent nanoparticle tracers have luminescent nanoparticle cores coupled to a luminescent substrate. The substrate is a large-particle size phosphor, while the nanoparticles are photoluminescent quantum dots (QDs) whose emission spectra can be tuned based on their chemical composition, size, and fabrication (e.g., dopants). The QDs are encapsulated by a protective layer to form a nanoparticle core. The protective layer can shield the QDs from external environments that would otherwise damage the delicate QDs. The substrate is also encapsulated by a protective layer, and the protective layer of the nanoparticle core is coupled to the protective layer of the substrate via a molecular linker to form a tracer particle complex. The tracer particle complexes can be disposed in a silicate suspension for subsequent use.