I don't think that the necklace in Al13's photo shows the necklace being auctioned. Unfortunately, the poor quality of the photo makes it difficult to discern the details of the necklace. I have found another photo showing what I think is the same necklace as in Al13's first photo (in the duo).



The darker fabric in the dress makes it a trifle easier to see parts of the pattern of the necklace, although the bottom section is more obscured.

I think it is the same as the one worn by the Empress in Al13's photo.