If it was gifted or given to your aunt, she does not need to return it: once something is gifted to another, it is hers.If your aunt had only borrowed the jewlery while your mother was alive, with the expectation or agreement to return it, or took it after your mother passed, then she has to give it back unless your mother had a will leaving it your aunt; in the absence of a will, if there is no surviving spouse, an only child gets everything. You could, if necessary, sue her for the return of the jewlery or its monetary value.