Cloisonne lamp with enamel and gilt

I know nothing about lamps at all. This was given to me by my stepmother, who frequents estate sales. I have no idea where it came from or how much she paid for it. I haven't even cleaned it, as I'm not sure what to clean it with or how it should be done. Absolutely clueless as to whether it's trash or treasure.

The lamp is approx. 28" tall bottom to tip, the ceramic lamp itself is around 12" tall. It looks as if the base has been replaced, due to the broken bottom shown in picture. There are no markings anywhere, other than the letters "ON" shown in picture. The base is screwed in tightly, and I cannot move it to see the rest of the marking. The colours are a cream base with arms of green throughout. It looks handpainted, mostly in pinks with yellow, green, blue and brown. There is a gold (gilt?) overlay and leafing.

I'm happy to do my best to answer any questions.

I'm willing to sell it, but would at least like the vaguest clue of what it is.