Noble gas and metal atoms form minimum-energy clusters. Here, we present analogous agglomerates of gold nanoparticles formed in oil-in-water emulsions. We exclude interfacial templating and nucleation-and-growth as formation mechanisms of these supraparticles. Similar to atomic clusters, the supraparticles form when a mobile precursor state can reconfigure until the nanoparticles' interactions with each other and with the liquid-liquid interface are maximized. This formation mechanism is in striking contrast to that previously reported for microparticle clusters.