These pieces of jewelry were created by using cloisonné enameling technique.
What is cloisonné enamel:
Cloisonné enamel is a jewelry technique that uses thin strips of wire (copper, silver or gold) to create designs on metal objects. Then the areas (partitions: cloisons in French) between the wires are filled with vitreous enamel, that is melted (fired) in between the strips. The final product is a beautiful combination of thin metallic line work and colored glass.