I am not so good when it comes to the layered sommerso pieces. The layers in the neck of your vase made me suspect your vase is Chinese, but I was not sure. In many Chinese pieces, the colored layers come very close to the surface of the vase and sometimes lose distinction. There is often inconsistencies in the thickness of the layers around the vase. Again, I am not so good with these types of pieces, so other people may have a better idea.