Listen as former curator Dedo von Kerssenbrock-Krosigk describes this goblet made of gold ruby glass. Gold ruby glass is one of the most difficult colors to achieve in glass because it consists of gold that has been added to the solution of the glass, where it dissolves into small particles, so-called colloids, during the heating and forming processes. Colloids have to have a very specific shape and an equal distribution within the glass in order to produce an even ruby color. The principle of coloring glass with gold was probably known since early antiquity, but Johannes Kunkel was the first to achieve the difficult process of producing very large gold ruby glass vessels.
Unfortunately, the foot and cover of this vessel are missing, and its surface is crizzling. Crizzling is a process of crystallization and deterioration of the glass that derives from a mismatched glass batch composition and is characteristic particularly of the early stage of baroque glassmaking in 17th-century Europe.