You cannot send a cross necklace - but an inmate is allowed to have it. What you might be able to do is speak with a counselor or case manager and tell them your desire. They might make arrangements for you to send it to them and then they would give it to the inmate, OR check to see if you can bring it to visitation.

Also, InmateAid has a wide variety of Birthday Cards that are only $0.99 each.