“…Among the abundant kinds of fillers, carbon black (CB) is confirmed to be most efficient in reinforcing rubbers and, therefore, most widely used in the rubber industry. , However, the energy consumption in the manufacturing process and utilization of nonrenewable feedstock, i.e., the heavy hydrocarbons, for producing carbon black make it unsustainable. Also, the carbon footprint for making carbon black is tremendous due to the partial combustion of heavy hydrocarbons, which release over 2 tons of carbon dioxide for producing 1 ton of carbon black. , Therefore, alternative feedstock has been considered as substitutes for producing reinforcing filler of rubbers, especially the ones from potential recyclable waste materials and industrial/agriculture byproducts. − Also, in some formulations of multifunctional elastomers, the total or partial replacement of conventional fillers (e.g., CB) with unconventional ones has been realized. − On the other hand, studies on the reinforcement mechanism indicate that while the chemical nature of the fillers or additives, which determines the filler–rubber interaction, appears to be vital for reinforcing rubber composites, the size of the fillers or additives is also of prime importance in elastomer reinforcement. , It is suggested that any kind of fine particles with a desirable small size can reinforce rubbers . In this case, the abundant natural minerals may be another alternative way for providing substitutes of carbon black, which is important for utilization of natural resources and environmental friendliness. − …”