An early 20th century coral, onyx and diamond pendant

An early 20th century coral, onyx and diamond pendant
The oval coral, corallium rubrum, plaque mounted with an onyx cameo of a lady facing left within a rose-cut border and onyx and diamond floral accents at the edge, glazed compartment to the reverse, to an onyx and diamond surmount of geometric design, suspended from a fancy-link chain, mounted in gold and platinum, circa 1920, pendant 6.7cm long, chain 51.0cm long