Silsilah as-Sahihah 1654 — Black Stone could have been a cure, but

It is narrated from Sayyiduna Abdullah bin Amr (may Allah be pleased with him) that the Noble Prophet (peace and blessings be upon him) said: "If the impurities of ignorance had not touched it (the Black Stone), then when an afflicted person touched it, he would be cured, and this (the Black Stone) is the only thing on earth that has been brought from Paradise."