Champelevé
Champlevé is a form of enamel-work in which hollow indentations are made in a metal surface which then is filled with coloured enamel. Some of the most sought after pieces originate in Russia (Imperial Era).
One of the renown silversmiths for Russian Champlevé pieces was Ivan Khlebnikov (Иван Хлебников) who was appointed as one of the Imperial Court suppliers of Russia along with being appointed with royal warrants from other nations such as Denmark and Holland.
Note: Not to be mistaken with Cloisonné.