Scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive analysis of X-ray (EDX), UV-vis spectroscopy, and X-ray diffraction are used to characterize different aspects of nanoparticles. Both SEM and TEM can be used to visualize the location, size, and morphology of the nanoparticles, while UV-vis spectroscopy can be used to confirm the metallic nature, size and aggregation level. Energy dispersive analysis of X-ray is used to determine elemental composition, and X-ray diffraction is used to determine chemical composition and crystallographic structure. UV-Vis absorption peaks for silver, gold, and cadmium sulfide nanoparticles can vary depending on particle size: 25-50 nm silver particles peak ca. 415 nm, gold nanoparticles 30-40 nm peak ca. 450 nm, while a cadmium sulfide absorption edge ca. 450 is indicative of quantum size particles. Larger nanoparticle of each type will have UV-Vis absorption peaks or edges that shift to longer wavelengths while smaller nanoparticles will have UV-Vis absorption peaks or edges that shift to shorter wavelengths.