Sherin,
Is the necklace possibly at a resort hotel or motel you stayed at last? Or is it in an upstairs bedroom in the home? Will you be taking a journey for a short vacation with a relative and could it be in her possession?
The reason I ask is Jupiter (the object 2nd) is natural lord of the 9th house of long journeys, sign Cancer is there so the journey may be a short one and play a role in the return of the necklace. The necklace could possibly be in the possession of a relative (9th) a woman (Cancer upon the 9th of uncles aunts long distance relatives) whom you may take a short jaunt with as mentioned above, or it might be in a relatives possession. Have you considered the object might be in the bedroom of a relative you associated with recently? (Cancer on the 9th with Jupiter in the 4th from the 9th puts the object in another's home.) You could get in contact with the relatives (Moon your co lord and the objects co rulership is sextile Jupiter in Libra in the 12th) also speaks of the possession in the hands of an older relative or past marriage partner or clandestine romantic partner of interest?
Jupiter in the sign of Libra suggests it hidden within a bedroom (Libra) or that you misplaced it somewhere when you were in public (Libra a public sign on a 12th house scenario suggests you went to a public place and forgot (12th) you misplaced it in a secluded area.
Your lord Mars will be opposing your best efforts to retrieve it personally/physically (Mars opposition to your Asc.) But the Moon as a feminine planet in a long journeying sign (Sag.) sextiling Jupiter from the 2nd gives you the opportunity to make efforts to retrieve the necklace should you scout about communicating with relatives about the valued object.
The Moon (your co lord or ruler) is within the 2nd house and will move to a sextile (opportunity) re-uniting you with your necklace, as Jupiter (necklace) is retrograde it is significant that the necklace will be returning to its owner.Then there is the Venus/Mars mutual reception that brings the efforts you make to retrieve it beneficial for you.
You Asc. in the Via Combusta is not a hopeful indication your personal efforts will locate it but it will come back to you by a woman (Moon sextiling Jupiter)
Is the object golden (Sun) and round? Combusting Venus and Mercury could be diminishing your awareness of its where abouts. The sign of Leo on the 10th makes me think a youth has it or you had it in a public tavern. Leo the Sun combusting Venus, Mercury suggests you might have been tipsy and not realizing it slipped from your person and it is obscured somewhere in the tavern hidden from view.
(Sun in the 5th combusting Venus natural lord of possessions, a place of fun, or entertainment, where you didn't enjoy yourself much, Mercury combust= hazy thoughts or the inability to recollect the place of its last visitation to view point.
There are a myriad amount of places you may remember you might have misplaced it but the most promising indication you will have some recollection where it may be is the Moon in long journeying Sagittarius on the 2nd house in the future.
All the best
Vyri