We lost a lot of my wife's jewelry, and there is no possibility of theft. Therefore, is it possible that the Jinn stole it?

All perfect praise be to Allaah, the Lord of the worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad, sallallaahu ‘alayhi wa sallam, is His Slave and Messenger.

Lost jewelry might have been kept in a place which you cannot remember.  It is possible that the Jinn could have stolen it. However, it is established in the Sunnah (Prophetic tradition) that the Prophet, sallallaahu ‘alayhi wa sallam, said that the Jinn neither open a shut door, nor unfasten a tied string, nor uncover a utensil, provided that the Name of Allaah The Almighty has been recited over it. [Al-Muwatta’, Al-Bukhari and Muslim]

This Hadeeth (narration) tells us that anyone who closes his door and mentions the Name of Allaah The Almighty, Satan neither opens the door nor steals  any possessions. The Hadeeth may be referring to  what occurs in some places, where people employ Jinn to  fetch them possessions belonging to other people. However, Jinn cannot take anything from a closed place, and over which the Name of Allaah The Almighty has been recited.

Allaah Knows best.