First of all, we’d like to state that it is not permissible for male Muslims to wear necklaces of any kind, because it involves imitating women, a thing which is totally prohibited and makes the person subject to Allah’s curse.

Sheikh Yusuf Al-Qaradawi, in his well-known book, the Lawful and the Prohibited in Islam states that: The Prophet (peace and blessings be upon him) declared that a woman should not wear a man’s clothing or vice versa. He cursed men who imitate women and women who imitate men. (Reported by Al-Bukhari and others.) Aspects of such imitation include the manner of speaking, walking, dressing, moving and so on.

The evil of such conduct, which affects both the life of the individual and that of the society, is that it constitutes a rebellion against the natural ordering of things. According to this natural order, there are men and there are women, and each of the two sexes has its own distinctive characteristics. However, if men become effeminate and women masculinized, this natural order will be reversed and will disintegrate.
Among those who are cursed by Allah and His Angels, both in this world and in the Hereafter, the Prophet, peace and blessings be on him, has mentioned the man whom Allah has created as male but who becomes effeminate by imitating women, and a woman whom Allah has created as female but who becomes masculinized by imitating men.
For this reason, the Prophet (peace and blessings be upon him) forbade men from wearing clothes or things pertaining to women
In his SahihImam Muslim reports that Ibn `Umar (may Allah be pleased with him) said: “The Prophet (peace and blessings be upon him) saw me wearing two garments having bold designs, and he said, ‘This is what unbelievers wear. Do not wear such things.’”

Based on the above-mentioned, Muslim scholars have concluded that it is forbidden for male Muslims to wear any golden or silvery necklace, just as it is forbidden for them to imitate women. Apart from all that, male Muslims are allowed to wear anything as long as they keep away from extravagance and from imitating disbelievers.
Thus, it is not allowed for male Muslims to wear necklaces of any kind, because it involves imitating women, a thing which is totally prohibited and makes the person subject to Allah’s curse.