Museum no. 5575-1859
The glass used in this ewer is known as 'Calcedoni' and imitates chalcedony, a naturally occurring hardstone. The ancient Romans were specialists at using glass to imitate semi-precious stones. The Venetians developed 'Calcedoni' glass on the island of Murano around 1450. Details concerning its manufacture were kept secret for many decades to prevent imitation and competition. The process involves mixing different colours of glass in layers as a special heat treatment during blowing.