Genuine Murano Glass made on the island of Murano Italy. Calcedonia, developed in the mid-15th century, is one of the most ancient and rare types of Murano Glass. The alluring striations, achieved by adding silver nitrate, become wonderfully unpredictable creating works of unparalleled beauty. Murano Glass Certificate of Authenticity included with each item. As each item is individually handcrafted, no two pieces are exactly alike with slight variations in size and color.