It is narrated from Sayyiduna Ibn Abbas (may Allah be pleased with them both) that the Prophet (peace and blessings be upon him) brought out a piece of gold and a piece of silk in his hand and said: "These two have been made unlawful for the men of my Ummah and lawful for their women."
Hadith Referenceالمعجم الكبير للطبراني / باب العين / 10843