General properties of strongly coupled colloidal plasmas are briefly summarised, and their properties of being able to “condense” into a self-organised liquid and crystalline form is discussed. Both laboratory and microgravity aspects of the research into this new form of matter are described and the theoretical constraints are compared with available measurements. Finally, the phase transition solid-liquid-gaseous is investigated using measurements of the “normalised interaction cross section,” ∑σp, derived from “molecular diffusion of the colloid component.