The Messenger of Allah ﷺ said, "The Black Stone descended from Paradise whiter than milk, but the sins of the children of Adam blackened it."
حدثنا قتيبة حدثنا جرير عن عطاء بن السائب عن سعيد بن جبير
قال رسول الله ﷺ نزل الحجر الأسود من الجنة وهو أشد بياضا من اللبن فسودته خطايا بني آدم
[Hasan]. Nasai also narrated it (5/226, no. 2938, Rites of Hajj, chapter on mention of the Black Stone) from the hadith of Ata bin Saaib with this wording, and Ibn Khuzayma graded it sahih (no. 2733). The hadith has many corroborating narrations in Targheeb wa Tarheeb (2/194, 195) and elsewhere.On this subject there is also a narration from Abdullah bin Amr [to come, no. 878] and from Abu Hurairah [Ibn Majah, no. 2957].