Some ruyi scepters are made of metal including gold, silver, copper and iron. They are worked with techniques including inlays and filigree. Those made of gold, silver and copper are mostly decorated with incised floral patterns. In the Ming dynasty (1368-1644) iron ruyi scepters with silver inlays were offerings for the Buddha. Ones with gold and silver filigrees were technically the most complex. Those inlaid with pearls, diamonds, and carved jades in the form of dragons, phoenixes and flowers are considered the most precious. Most of the metal ruyi scepters in the Palace Museum collection were made for or purchased by the imperial household in the late Qing dynasty (1644-1911) for imperial birthdays or weddings.