Hajar aswad

Hajar aswad is a round, black-colored ruby, located in the southeastern corner of the Ka'ba or the left of Multazam (between the Black Stone and the Kaaba's door). Height about 150 centimeters, above ground.
This stone is black because it is called as hajar which means stone and aswad which means black. Formerly Black Aswad is white and is a stone from heaven. The amount of human sin causes the stone to become black.