<p>A set of ancient chime stone excavated from the tomb of the Marquis of Haihun dating back to the Western Han dynasty has drawn the interest of archaeologists owing to its distinctive armor-like crust that retains the original outline of the instruments. In this research, we employ a range of analytical techniques to elucidate the material characteristics and formation mechanisms of the associated weathering products. The results demonstrate that intense chemical weathering led to powdery disintegration and severe dissolution of the carbonate matrix. Prior to this deterioration, however, siderite-rich crusts had formed on the surface through a process involving the dissolution of parent calcite and precipitation of secondary siderite within the anthropogenically modified microenvironment of the sealed tomb. Crucially, the rare occurrence of pseudomorphic substitution effectively preserved the original surface morphology and outer contours of the chime stones, laying an essential foundation for their further restoration.</p>