The relevance of anisotropic interactions in colloidal systems has recently emerged in the context of rational design of novel soft materials. Theoretical studies have predicted the possibility of a gas-liquid phase separation confined at low densiti
es and the formation of empty liquids and equilibrium gels in low-valence systems. Here we provide experimental evidence of this scenario in Laponite, a complex colloidal clay with discotic shape and anisotropic interactions. We also report simulations of a patchy model for Laponite platelets, able to reproduce the observed experimental phase diagram and structural properties, confirming the crucial role of the reduced valence.
