Ancient Roman glass measures 15mm in diameter and hangs from an 18-inch, 1mm box chain with spring ring closure. Color of Roman glass will vary. Comes with Certificate of Authenticity. .925 sterling silver. ABOUT ANCIENT ROMAN GLASS JEWELRY - Ancient Roman Glass jewelry blends the mystique and romance of the ancient world, a unique beauty shaped by the forces of nature, and skilled modern craftsmanship. The result is a wearable piece of history that, with proper care, will be treasured for generations to come. THE HISTORY - Almost 2,000 years ago, the Roman Empire was the birthplace of new glass blowing techniques used to create items like plates, vases, bowls, and jars. Today, this ancient glass can be recovered in archaeological sites in Israel, which was a major center for glass production during ancient times. Because Roman Glass jewelry is made of fragments of these ancient hand-blown glass objects, each piece varies in shape, thickness and color. Every piece of Roman Glass jewelry is one-of-a-kind. NATURE'S TOUCH - The striking colors found in Roman Glass jewelry come from a thin natural layer called the “patina” that formed over the course of centuries as the glass lay in mineral-rich soil. Through a process of oxidation, the patina developed these beautiful and complex shades of blue, green, and other colors. MODERN CRAFTSMANSHIP - Skilled artisans carefully choose ancient glass fragments, clean them to reveal their colorful natural patina, cut and shape the glass, and mount the glass to make a finished piece of top-quality jewelry. Designers craft jewelry that calls to mind the ancient past, in a wide variety of modern styles.