Bukhari

Hadith Commentary:
This narration makes it clear that the use of a gold ring is absolutely haram (forbidden) for men; whoever considers it halal (permissible) falls into disbelief. However, it is permissible for women to use gold.

Hadith Commentary:
(1)
Undoubtedly, a gold ring is forbidden (haram) for men. It is narrated from Aisha radi Allahu anha that the king of Abyssinia, Najashi, sent some jewelry as a gift to the Messenger of Allah sallallahu alayhi wa sallam. Among them was a gold ring whose gem was in the Abyssinian style. The Messenger of Allah sallallahu alayhi wa sallam, turning away from it, held it with a stick or his finger and, calling his granddaughter Imamāh bint Abi al-As radi Allahu anha, said: “Daughter! You wear it.” (Sunan Abi Dawud, al-Khatam, Hadith: 4235) If gold had been lawful (halal) for men, he would not have turned away from it, and if it were not permissible for women to wear gold, the Messenger of Allah sallallahu alayhi wa sallam would never have made his granddaughter Imamāh radi Allahu anha wear it.

(2)
Although it is transmitted from some of the noble Companions radi Allahu anhum that they used to wear gold rings, it is possible that the hadiths of prohibition did not reach them. It is strange that a hadith of prohibition is narrated from al-Bara’ ibn Azib radi Allahu anhu, yet he also used to wear a gold ring, and people would say to him: “Why do you wear a gold ring when the Messenger of Allah sallallahu alayhi wa sallam has forbidden it?” He would reply: “When the Messenger of Allah sallallahu alayhi wa sallam gave me the ring, he said: ‘Wear it, for Allah and His Messenger have made you wear it.’” Perhaps he considered this as a specific allowance for himself. In any case, it is not permissible for men to wear it. And Allah knows best. (Fath al-Bari: 10/391)

Hadith Commentary: Benefits and Issues: For men, wearing a gold ring is unanimously prohibited (haram). If any Companion (sahabi) wore a gold ring, it must have been because they were not yet aware of this prohibition, or they remained upon the initial permissibility at the beginning of Islam. And as for the narration transmitted from al-Bara’ ibn Azib radi Allahu anhu regarding wearing a gold ring, even if we assume it to be authentic...

...since the narration prohibiting it from him has already been mentioned in Sahih Muslim, he may have considered the prohibition to be one of dislike (tanzih), or, since the Messenger of Allah sallallahu alayhi wa sallam himself made him wear it, he may have considered himself to have a special dispensation (khususiyya) in this matter. (Fath al-Bari, Dar al-Ma’rifah, vol. 10, p. 317)

And for women, it is permissible, because the Prophet himself made Ummamah bint Abi al-As wear it. (Musannaf Ibn Abi Shaybah, vol. 8, p. 278)

And upon this, according to Imam Nawawi, there is consensus (ijma‘) among the Muslims that for women, wearing a gold ring is permissible, and for men, it is prohibited (haram). And Ibn Hazm’s view permitting gold rings for men, or the view of some that it is disliked (makruh), is contrary to consensus (ijma‘). The Ibn Hazm referred to here is Abu Bakr ibn Muhammad ibn ‘Amr ibn Muhammad ibn Hazm, and to attribute this to Ibn Hazm al-Zahiri is an extreme boldness.

The above-mentioned matters are not specific only to Ali (radi Allahu anhu); rather, they apply to all men of the Ummah. For details, see: 5175.