The Color Origin of the Elephant Skin Held by the Copper Gilt Chakrasamvara

Using portable microscopy, metallographic microscopy, environmental scanning electron microscopy and energy dispersive spectrometer (ESEM-EDS), micro area X-ray diffraction and other analysis methods, the color origin of the elephant skin held by a copper gilt Chakrasamvara in the collection of the Palace Museum was analyzed. The results indicate that the elephant skin substrate was a silver copper alloy, and the black substance on the surface of the elephant skin was a uniform and flat layer of silver sulfide. The black substance on the surface of the statue of Chakrasamvara was pure silver/sulfur niello. Based on historical records and the microscopic morphology of the elephant skin fragments, the method of making niello on the surface of the elephant skin was speculated.