Murano Glass Heart Pendant Necklace Calcedonia. Calcedonia, developed in the mid-15th century, is one of the most ancient and rare types of Murano Glass. This exquisite pendant offers a stunning display of design presented on a 19” black cord creating an elegant addition to any jewelry collection. The extraordinary quality and elegant design of this hand blown pendant, 1.75" x 1.5", is presented in a black jewelry box tied with a gold cord. Each pendant is stamped Murano Italy on the reverse side of the pendant and a Murano Glass Certificate of Authenticity is included with each piece. A Murano Glass Pendant Necklace is the perfect gift idea for her for any occasion such as Birthdays, Anniversaries, Valentine's Day, and Mother's Day. Gift messaging available. It's also the special final touch to complement any outfit. As each pendant is individually handcrafted, no two pieces are exactly alike with slight variations in size and color.