Opal is my favorite gemstone so it follows that I love iridescent bottles. What a wonderful piece, I'd kill to get one of those! Do NOT tumble it, myself and others would likely pay a premium with the patina intact if it's for sale. How did you come across it?
I wouldn't even touch that with bare hands.. what an awesome patina! Too bad it's the rarer, much more valuable variant, or else I'd be throwing you a nice offer..!!
This is the best looking example I can imagine because it really makes the embossing stand out and it doesn't even look real anymore, looks like a painting....Jim