What is the ruling on an engagement or wedding ring for men, and is it permissible for it to be other than gold, and what other metals are forbidden for men?

It is not permissible for a Muslim man to wear a gold ring, but he may wear rings made of silver or other metals. As for the "double ring" (wedding ring), it is not a custom of Muslims, and it becomes forbidden if it is accompanied by the belief that it affects the marital relationship (which is considered shirk - polytheism), or if it is an imitation of non-Muslims. Furthermore, it is not permissible for the fiancé to put the ring on his fiancée himself, because she is still a stranger to him.