HHhhmmmm? It kinda looks like a white crown that someone brush painted blue. I recently bought an all green crown at a farm auction and it was a painted over gold crown. It took a lot of hours to get all the paint off and make it look decent though! I wouldn't ever do it again!
If it has a metal screw on base, its probably a painted crown. If it has a glass flange base, its a reproduction/fantasy.

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