Plaque

A plaque (from French: plate) is a large central and decorated plate of metal, cameo, intaglio or other material. These are set in rims and worked in jewelry, either as a series (as in en esclavage necklaces) or single.
Mid-Century Opal and Rose-Cut Diamond Necklace Composed of Scalloped Plaques Connected by Oval Links.

Mid-Century Opal and Rose-Cut Diamond Necklace Composed of Scalloped Plaques Connected by Oval Links.