Iron Campo del Cielo 280g TUMBLED!! Provenance IMCA member Certificate of Authenticity IMCA NO RESERVE!! The tumbling is a process formed by 4 different steps: grinding, smoothing, polishing and shining. The purpose of the tumbling process is obtaining a shiny and “flat” surface without flaws. The grinding is the first step of the process, where the most accentuated flaws are removed. The smoothing is the second step of the tumbling process, where smaller flaws and the residuals of grinding process are removed. The polishingis the third step of the tumbling process. The shining is the last step of this specific process: it is the final phase, the piece to be treated will be brilliant and the surface will be shiny as a mirror – without any surface flaws.