Original Antique 14K Imperial Russian 56 Gold Opal Brooch Pin Romanov Jewelry RU. This product data sheet is originally written in English. Antique Imperial 14K Russian 56 Gold Natural Opal Brooch Pin. Weight is 2.2 grams. Fully hallmarked with workmaster/ silversmith/ maker's mark initials. Kokoshnik mark for 14K Imperial Russian Gold. Natural Opal gemset at center. Opal measures approximately 8mm X 5mm.