These are a set of beveled glass sidelights. They are engraved, fully beveled, and are accentuated with clear jewels. They are assembled with a colonial shaped zinc. Because zinc is a rolled formed material it requires special tooling to form it into a curve. Fitting of each joint is a more laborious procedure, requiring special grinding wheels which notch the ends of the colonial shape. In the craftsmen’s world this notching technique is termed a jack mitre.
Here is a close up of the engraved centerpiece. There are 24 separate bevels around the engraved centerpiece. The piece is bordered by 12 eye shaped peak bevels, separated by clear jewels.