Seated bodhisattva Avalokiteshvara (Guanyin)

Gilding Technique and Portable Buddhas of the Yuan, Ming, and Qing Dynasties
Gold was scarce and expensive in ancient China, and it was often imitated with bronze thinly coated in gold. This technique, known as “mercury gilding,” involved an application of a paste-like mixture of gold and mercury on bronze to create a gilded surface, which also gave the metal greater resistance to tarnishing. The bronze was heated by charcoal fire to evaporate the mercury, leaving the gold bonded to its surface. This gold surface layer was then burnished with a hard, smooth metal or stone tool to make it more compact and shiny.
The use of gold on bronze in China dates back more than two thousand years, and this high-cost technique was traditionally used for luxurious decorations and icons. Many bronze-cast buddha and bodhisattva statues were adorned with this gilding technique to attract more devotees. Small, lustrous figures and icons like these in the cases were carried for spiritual protection on journeys and placed on household altars for worship. It is important to note that many altar shrines were made in segments and then assembled, and so over the centuries some have lost attachments or have had parts from similar-sized works reattached.