Mine is the only one that I see in trades or user shops right now. What should I consider a "fair" offer, on the understanding that I don't really care if I sell it quickly or not, and that worth is defined by what others are willing to pay?

Thanks for any advice I might get.

It comes from the November 2011 Collection which is sitting in shops just under 27m. I would consider that the high end of a starting point for pricing.

Based on the price of the November 2011 Collection (where it comes from; price is currently at 26.9mil), I'd say you can sell it for around 10~20mil.
Of course, I could be very wrong; all I know is that people aren't going to pay more than the collection price.

Thank you both so much! Major brain cramp--I completely forgot to check the collection it came from because I got mine from a Lumineve Gift. I appreciate your responses.