Aventurin or avanturin glass was formerly made only in the Island of Murano, near Venice, but is now prepared throughout Germany, Italy, Austria, and France. It is a brown glass mass in which crystalline spangles of metallic copper according to [Friedrich] Wöhler (of protoxide of copper according to [Max Joseph] von Pettenkofer) appear dispersed. … The Bavarian and Bohemian glass-houses produce an aventurin glass rivalling the original.