Here is what I would do:
1.) Contact a specialist from Sotheby's or Christie's, both will look at it for free. You can even email one directly and send the pictures and they'll get back to you within a month probably (from my experience). Just tell them your story, and throw in something about "interested in selling with Sotheby's/Christie's"
2.) Second, visit the link posted by sevenseas and email a specialist there.
Really hope this helps! I occasionally do it with pieces I think are around $5k or more. Due to the story behind this goblet, it may take them a little longer, and they will most likely ask you to ship it to them if they think it's the real deal. Good luck!
