Small, spherical media employed within rock tumbling processes to enhance the polishing stage are designed to cushion stones and facilitate even distribution of abrasive compounds. These media, typically ceramic or plastic, prevent direct impact between rocks, reducing chipping and promoting a smoother, more uniform finish. An example would be adding these media during the final stage of tumbling, when using a fine polishing compound, to achieve a high-gloss sheen on the processed stones.
The incorporation of these materials is critical for achieving optimal results in rock tumbling. They prevent damage to softer stones and ensure that the polishing compound reaches all surfaces, including crevices and irregularities. Historically, various materials have been used for this purpose, evolving from natural substances to engineered polymers, each offering different levels of cushioning and durability, directly influencing the final polish quality and overall yield.