Colloids, micron-sized particles in a solvent, undergo Brownian motion, minimizing their free energy; thus, colloidal suspensions mimic the collective behavior of atoms and molecules. Colloids are sufficiently large for optical microscopy; this allows their behavior to be studied in great detail, which is not the case with atomic and molecular systems. During the last decade, significant scientific interest focused on spherical

colloids. However, much of the rich behavior of real atoms and molecules stems from their spherically-anisotropic shapes; perfectly spherical colloids are inappropriate as a model for these systems. Yet, very few direct structural studies of non-spherical colloids exist to date.

 We form fluid suspensions of colloidal ellipsoids (aspect ratio = 1.6) and detect the coordinates of all particles in three dimensions, employing direct confocal microscopy. To quantify the structure of our samples, at different densities, and compare this structure to common theoretical models, we measure the real-space pair-correlation function g(R), as well as the Voronoi cell volumes of individual particles. It is important to note that the experimental g(R) cannot be described by the common theoretical models, developed for the spherical particles. More advanced theoretical models, which take into account the non-sphericity of our colloids, are currently being tested.