A ruthenium-based electrode material for use with a spark plug. The electrode material comprises ruthenium (Ru) and a precious metal. The ruthenium (Ru) is the single largest constituent of the electrode material on a wt % basis. The electrode material may have a density that is less than or equal to about 15.5 g/cm3 and may include at least one other precious metal. The electrode material may be used in a spark plug that includes a metallic shell having an axial bore, an insulator having an axial bore and at least partially disposed within the axial bore of the metallic shell, a center electrode at least partially disposed within the axial bore of the insulator, and a ground electrode attached to a free end of the metallic shell. The center electrode, the ground electrode or both may be formed at least in part from the electrode alloy.