The conditions are as follows:
(1) The pebbles must be thrown aiming at the pillar of the Jamarah. If they are thrown at another target, it will not be valid even if they hit the pillar.
(2) The pebble must be thrown with force. Merely placing or touching the pebble there will not suffice.
(3) The pebble must be a stone. A piece of earth or brick will not suffice.
(4) The pebble must be thrown by hand. It will not be valid if it is launched using children’s toys, a slingshot, or an arrow, or by kicking it with the foot.
(5) The seven pebbles must not be thrown all at once by holding them in the fist; rather, each pebble must be taken in the hand and thrown separately.
(6) A used pebble may not be reused.
(7) The pebbles must be thrown when the prescribed time begins, neither before nor after it.