The Black Stone is set into the eastern corner of the Kaaba and marks the starting and ending point of each tawaf circuit. Pilgrims kiss it if possible, or touch it, or simply point toward it while saying "Allahu Akbar" when passing, without pushing or causing harm to others — the sunnah is followed as it is, not treated as having any inherent power.
This is made explicit in the well-known report of Umar ibn al-Khattab, who said while approaching it: "I know that you are a stone that can neither benefit nor harm; had I not seen the Messenger of Allah ﷺ kiss you, I would not have kissed you" (Sahih al-Bukhari 1597). This statement, from the second Caliph, has stood for centuries as a clear safeguard against any drift toward stone-worship among Muslims — the gesture is an act of following the Prophet's ﷺ example, not veneration of the object itself. Because of the density of crowds today, scholars remind pilgrims that kissing it is a sunnah, not an obligation, and that safety and gentleness with fellow pilgrims takes precedence over insisting on reaching it physically.