What is the ruling on throwing the jamarāt with pieces of cement or with fragments of large rocks after they have been broken into small pieces, and is the throwing required to be repeated if it was performed in that manner?

The majority of jurists stipulate that the stoning of the Jamarat must be done with pebbles (hasaa), which are small stones, and cement is not permissible according to them. They believe that the Prophet, peace and blessings be upon him, stoned with pebbles and commanded stoning with pebbles similar to those used for slingshots (hasaa al-khadhf). As for the Hanafis, they permit stoning with anything that is of the earth's kind, such as stones, clods of earth (madar), and clay. Therefore, if you stoned with pieces of cement that do not contain pebbles, your stoning is not valid according to the majority opinion, and you are obligated to offer a sheep (shat) to be distributed among the poor of the Haram, or to appoint someone to do so. If you are unable to afford the price of the sheep, then there is nothing upon you.