Wearing gold and silk is unlawful for males, since Islam considers them to be exclusive for women and a sign of femininity. The Prophet (peace be upon him) took a piece of silk and a piece of gold and said: “These two are forbidden for the men of my people.” [Sunan Abî Dâwûd]
He also said: "Wearing silk and gold has been made unlawful for the men of my people and lawful for the women." [Sunan al-Tirmidhî]
Therefore, it is forbidden for men to wear any kind of gold jewelry. It makes no difference if it is pure gold, 18 karat gold, white gold, or any colored alloy of gold. The ruling is the same as long as it is recognized as gold.
And Allah knows best.
Source: Islam Today