A non-combustible, synthetic fire-log is disclosed comprising a composition formed to approximate the shape of a combustible object, wherein said composition comprises a substantially non-combustible matrix and an effective amount of hollow spheres. In one embodiment, the effective amount of hollow spheres ranges from approximately 3 to 85 percent of the total composition by weight. The composition enhances the aesthetic quality of the synthetic fire-log when exposed to heat and also decreases the carbon monoxide emissions of synthetic fire-log systems.