Anas narrated that the Messenger of Allah said:
"While I was traveling through Paradise, a river appeared before me whose banks had tents of pearl. I said to the angel: 'What is this?' He said: 'This is Al-Kauthar, which Allah has granted you.'" He said: "Then he put his hand in the clay, and removed musk from it, then I was raised up to Sidrat Al-Muntaha so I saw a magnificent light at it." (IT)
English reference (IT): Vol. 5, Book 44, Hadith 3360 (IT)
Arabic reference (IT): Book 47, Hadith 3685 (IT)