It is narrated from Sayyiduna Ibn Abbas (may Allah be pleased with them both) that the Messenger of Allah (peace and blessings be upon him) said: "The Black Stone came from Paradise; it was whiter than snow, but the sins of the polytheists made it black."
Hadith Referenceمسند احمد / ومن مسند بني هاشم / 3537
Hadith Gradingحکم دارالسلام:صحيح دون قوله: وكان أشد بياضا ....، وإسناده ضعيف لاختلاط عطاء بن السائب