Cranberry glass

Cranberry glass is made in craft production rather than in large quantities, due to the high cost of the gold.

This is evidenced by the British Museum's collection Lycurgus Cup, a 4th-century Roman glass cage cup made of a dichroic glass, which shows a different colour depending on whether light is passing through it or reflecting from it; red (gold salts) when lit from behind and green (silver salts) when lit from in front.

[2][3] Kitab al-Asrar, an Arabic work attributed to Abu Bakr al-Razi contains one of the earliest modern descriptions of the preparation of gold ruby glass.

[4][5] The craft was then lost and rediscovered in the 17th century Bohemian period by either Johann Kunckel in Potsdam or by the Florentine glassmaker Antonio Neri.

Chemist and winner of the 1925 Nobel Prize in Chemistry Richard Adolf Zsigmondy was able to understand and explain that small colloids of gold were responsible for the red colour.