A question poped up in Christian SE asking if God in other religion was compared to a rock. I wonder if in Quran Allah is compared to a rock?
No. Chapter 112, Al-Ikhlas (The Purity) describes Allah as follows:
112:1 Say, "He is Allah , [who is] One, 112:2 Allah , the Eternal Refuge. 112:3 He neither begets nor is born, 112:4 Nor is there to Him any equivalent."
This is the message throughout the Quran. Allah is not comparable to anything or anyone.