Studying properties of phi-mesons produced in heavy-ion collisions can provide information about the hot and dense medium created in the collisions. Since the interaction cross-section for phi with other copiously produced hadrons is presumed to be small, and its lifetime relatively long (41 fm/c), the phi-meson should be a clean probe of the medium from the early stage of the system's evolution. Additionally, since the phi is a meson, and also has a mass comparable to baryons (e.g. p, Lambda) it may help to differentiate between particle-type (i.e. baryon/meson) and mass dependencies of particle production mechanisms in heavy ion collisions.
We will present results on the elliptic flow and transverse momentum distributions of phi-mesons measured in Au+Au collisions by the STAR experiment at RHIC. Collective flow and partonic collectivity will be discussed with the data. Finally we will make comparisons with the behavior of other particles and with model expectations.