I just had a glass of wine, and for some reason, I'm getting extremely clear impressions (although I have no idea if they are accurate):
The necklace is wrapped in a black or blue dress (made of a very soft material), in a drawer which is in the lower part of a tall wardrobe or bookshelf. It is in a well-lit room (probably a living-room) and the windows to the room are to the right of the bookshelf (as you look at it). Between the bookshelf and the windows there is an open doorway.
Waiting with excitement
Good luck to all participants!