Muslims believe that this stone fell from the sky during the time of Adam, and that it has the power to cleanse worshippers of their sins by absorbing them into itself. The Black Stone is believed to have originally been colored white, but it turned black because of the sins it has absorbed over the years.
As part of the Kaaba, the Black Stone resides in the city of Mecca. Muslims who have come to Mecca for the hajj try to kiss or touch the stone, or at least point to it, when they arrive at the Kaaba. Islam dictates that pilgrims circle the Kaaba seven times.