We have authentic narrations in Shia and Sunni books from the Prophet Muhammad (SAWA) stating that wearing gold is not allowed for men as well as wearing pure silk. Regarding gold we have an authentic Hadeeth from Ali ibn Jafar from his brother Imam Musa ibn Jafar (AS) when he was asked: Is it allowed for man to wear gold? He replied: No, because the Prophet (SAWA) did not allow it. ( Wasaa'il al-Shia, V.4, P.415). We have also a narration from Ammar ibn Moosa from Imam Jafar Al-Sadiq (AS): man should never wear nor pray with gold. (Wasaa'il al-Shia , V4, P. 413).
In Sunni books, Tirmithi and Ibn Hanbal and many others narrated that the Prophet (SAWA) said: Silk and gold are forbidden on the men of my Ummah, permissible for their women.
That is why it is unanimous among Muslim scholars from all Muslim sects that wearing gold ands silk is forbidden for Muslim men.