If you look at the Antiques Price, 2008, pages 462 and 464, you may see your chandelier, or something very similar. priced between $13,000 and $40,000 - I would certainly get a professional appraisal if you wish to sell it. It may be just enough different that it may not have much value at all - just be prudent. Good Luck!
Re: 18th Century Style Brass Chandelier