Cloisonné is an ancient technique for decorating metalwork objects, in recent centuries using vitreous enamel, and in older periods also inlays of cut gemstones, glass, and other materials.  The decoration on this vase is formed by first adding compartments to the metal vase by soldering or adhering precious metal to the outer edges. These remain visible in the finished piece, separating the different compartments of the enamel or inlays, which on this piece reveal a hue of lovely azure.