The Messenger of Allah said: "The Black Stone descended from the Paradise, and it was more white than milk, then it was blackened by the sins of the children of Adam."
Jami` at-Tirmidhi Book 9, Hadith 70
← Previous Hadith "I wanted to enter the House to perform Salat in it, so the Messenger of Allah took me by the hand and put me in the Hijr, and he said: 'Perform Salat in the Hijri if you want to enter the House. For indeed it is part of the House, but your people considered it insignificant when they built the Ka'bah, so they put it outside the House.'"

Jami` at-Tirmidhi Book 9, Hadith 69 Next Hadith → He heard the Messenger of Allah saying: "Indeed the Corner and the Maqam are two corundums from the corundum of Paradise. Allah removed their lights, and if their lights had not been removed then they would illuminate what is between east and the west."

Jami` at-Tirmidhi Book 9, Hadith 71