Louie, there is a style of decoration called "cloisonné" in which a very thin band of gold or silver is used, with glass or cut gem stone material making up the design. It uses some very small tools to bend the metal. So you may search for "Cloisonné" making or tools. Would probably have to anneal the brass pretty frequently. Junctions are made with very low-temp solder.
That is a fantastic black and white horn that you made, and my mind is reeling at the complexity of the simplicity involved, if you can understand that! Plain ol' black and white - but what a fantastic job of blending them!