Renaissance-revival gold and emerald cameo gem-set pendant, Castellani, circa 1870

Set in the center with a 19th century emerald cameo of the Madonna, held within a clawed collet applied with black enamel, within an openwork frame of scroll design decorated with green and black enamel, alternately set with rubies and diamonds, the latter in high squared collets enameled in black, unsigned. 

Sotheby's London, July 12, 1984, lot 176.

Castellani and Italian Archaeological Jewels, The Bard Graduate Center, New York, November 2004-February 2005, p. 368, no. 142. Also exhibited at Somerset House, London, May -September 2005 and Villa Giulia, Rome, November 2005-February 2006.  

The style of the clawed collet holding the emerald in the center of this brooch, as well as the squared collets of the rubies, all enameled in black, are identical to those found in Castellani's repertoire, illustrated in color by Geoffrey C. Munn, Castellani and Giuliano, Revivalist Jewelers of the 19th Century,   pl. 181-183.