From Sahih Muslim (Hadith 3494):
Abd al-Rahman b. 'Auf (Allah be pleased with him) reported that Allah's Messenger (ﷺ) 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
Reference: Muslim 3494