15:74
فَجَعَلْنَا عَـٰلِيَهَا سَافِلَهَا وَأَمْطَرْنَا عَلَيْهِمْ حِجَارَةًۭ مِّن سِجِّيلٍ ٧٤
Saheeh International
And We made the highest part [of the city] its lowest and rained upon them stones of hard clay.
Tafsir of "Ibn Kathir" (English)
And We turned them upside down and rained stones of baked clay upon them. The discussion of As-Sijjil in Surah Hud is a sufficient explanation.Allah said:إِنَّ فِي ذَلِكَ لايَاتٍ لِّلْمُتَوَسِّمِينَ