There is a Hadith in Zujajatul Masabeeh on the authority of Musnad Ahmed bin Hambal, Sunan Abu Dawood and Sunan Nasai:
Translation: It is narrated on the authority of Hadhrat Ali (May Allah be well pleased with him) that the Holy Prophet (Sallallahu alaihi wa sallam) took silk in His right hand and took gold in His left hand. Then He (Sallallahu alaihi wa sallam) said: Verily! These 2 things are forbidden for the men of My Ummah. Wearing a golden ring is not allowed for men. In engagement, in the customs of marriage or on some other occasion, giving a golden ring to man to wear is an entirely Unislamic tradition and is against the Shariah. There are strict warnings for the men who wear golden rings. The Holy Prophet (Sallallahu alaihi wa sallam) expressed His displeasure about such a person and declared it as a spark of fire for the person wearing it.
There is a Hadith in Zujajatul Masabeeh, Vol. 3, Pg No: 394 on the authority of Sahih Muslim:
Translation: It is narrated on the authority of Hadhrat Abdullah bin Abbas (May Allah be well pleased with them) that the Holy Prophet (Sallallahu alaihi wa sallam) saw a golden ring in a man’s hand, He (Sallallahu alaihi wa sallam) removed it, threw it away and said: Does any one of you desire a spark of fire and keeps it in his hand? After the Holy Prophet (Sallallahu alaihi wa sallam) went away, that person was told to take his ring and use it. He said: By Allah Most High! I will never take it when the Holy Prophet (Sallallahu alaihi wa sallam) has thrown it. (Sahih Muslim, Vol. 2, Pg No. 591)
The above mentioned Hadith make it clear that wearing gold and using it is not permissible for men. There is no allowance for men to use rings and other such adornments. If a gift is being given to a man, then instead of a golden ring, some money or some other thing which a man can use should be given.
As given in Fatawa A’alamgiri, Vol. 5, Pg No: 335 and Durre Mukhtaar, Vol. 5, Pg No: 253.
It is permissible for a man to wear a silver ring weighing less than 3.03775 gm (called a mithqaal in Urdu). Apart from this wearing any kind of gold or silver jewelry is forbidden (Haraam) and wearing jewelry made of other metals like steel etc. in Makruh, (Undesirable).
That the band is to be considered and not the gemstone is true. However, it doesn’t mean that gold can be used in place of the gemstone. What it means is that the weight given above is only the weight of the band and doesn’t include the weight of the gemstone. With the gemstone, the weight of the ring may exceed 3.03775 grams. It should also be remembered that it is permissible to use any gemstone in a ring of silver, but it is not correct to make the band out of any gemstone. Gold is expressly forbidden, both as the band and as the gemstone.
As mentioned in Al Hidayah, Kitaab Ul Karahiyya.
So men should avoid wearing jewelry made of any metal etc. But for women it is permissible to wear jewelry made of gold, silver or of any other metal. As given in Radd Ul Muhtaar, Vol. 5 Pg. No. 254 and in Fatawa A'alamgiri Vol. 5, Pg. No. 359.