Is it permissible for a woman who wears the prescribed Islamic Hijab to display her jewels?
It is not permissible for a woman to display her jewels in the presence of Ajanib (men other than a spouse and permanently unmarriageable relatives), because they are ornaments and Allah (Glorified be He) says:
...and not to reveal their adornment except to their husbands
May Allah grant us success. May peace and blessings be upon our Prophet Muhammad, his family, and Companions.