Analysis of Pigments Unearthed from the Yungang Grottoes Archaeological Excavations

Abstract

The Yungang Grottoes, excavated during the 5th to 6th centuries AD, stand as a pinnacle of Buddhist sculpture, representing a precious world cultural heritage. Since their excavation, the grottoes have undergone multiple phases of painting, with a significant amount of pigment still present on the surfaces of the stone carvings. Since the 1990s, two large-scale archaeological excavations have been conducted on both the front ground and the summit of Yungang Grottoes. During these excavations, various artifacts with accompanying pigments were unearthed, encompassing stone carvings, grinding tools, architectural components, fragments of murals, and remnants of clay sculptures, spanning the historical periods of the Northern Wei, Liao-Jin, and Ming-Qing dynasties. Using portable X-ray fluorescence spectrometry, portable microscopy, polarizing microscopy, scanning electron microscopy–energy dispersive X-ray spectroscopy, and confocal Raman microscopy, we conducted a comprehensive analysis of these painted elements. The investigation revealed the presence of hematite, vermilion, goethite, malachite, calcium carbonate, lead white, and ivory black pigments in the Northern Wei samples. The Liao-Jin samples exhibited hematite, while the Ming-Qing samples contained vermilion, minium, atacamite, lead white, and Prussian blue.