Sahih Muslim Book 8, Hadith Number 3323.
Chapter: The dower.
Abd al-Rahman b. ‘Auf (Allah be pleased with him) reported that Allah’s Messenger (May peace be upon him) saw the signs of the happiness of wedding in me, and I said: I have married a woman of the Ansar. He said: How much Mahr have you paid? I said: For a date-stone weight of gold. And in the hadith transmitted by Ishaq (it is): (nawat weight) of gold.