Thanks for your post and for those pictures (your archive is impressive). There is no certain that the collier is a cartier piece, although is highly probable it is. It's destiny is a bit complicated to guess. First there is no reference that the piece is property of the Royal House but that doesn't mean it isn't. In second that piece was bought by D.Amelia herself when she was Duchess of Braganza so it was bought hypothetically with portuguese money. If so, it should have gone to the Duke. Third: But if it was Cartier, it means that it had not portuguese origin so it should have gone to Her french relatives. Quite confusing.