The fuel of Hell

The fuel of Hell are men and stones. Allah (swt) warns us in the Qur'an:

"O you who have believed, protect yourselves and your families from a Fire whose fuel is people and stones, over which are appointed angels, harsh and severe; they do not disobey Allah in what He commands them but do what they are commanded." [Qur'an, 66:6]

and, "Indeed, you [disbelievers] and what you worship other than Allah are the firewood of Hell. You will be coming to enter it." [Qur'an, 21:98]