• صَّخْر
• صَخْرَة

Appears 3 times in the Quran.

1. 18:63 قَالَ أَرَءَيْتَ إِذْ أَوَيْنَآ إِلَى ٱلصَّخْرَةِ فَإِنِّى نَسِيتُ ٱلْحُوتَ وَمَآ أَنسَىٰنِيهُ إِلَّا ٱلشَّيْطَٰنُ أَنْ أَذْكُرَهُۥ وَٱتَّخَذَ سَبِيلَهُۥ فِى ٱلْبَحْرِ عَجَبًا

   He said: Did you see when we took refuge on the rock then I forgot the fish, and nothing made me forget to speak of it but the Shaitan, and it took its way into the river; what a wonder!
   

2. 31:16 يَٰبُنَىَّ إِنَّهَآ إِن تَكُ مِثْقَالَ حَبَّةٍ مِّنْ خَرْدَلٍ فَتَكُن فِى صَخْرَةٍ أَوْ فِى ٱلسَّمَٰوَٰتِ أَوْ فِى ٱلْأَرْضِ يَأْتِ بِهَا ٱللَّهُ إِنَّ ٱللَّهَ لَطِيفٌ خَبِيرٌ

   O my son! surely if it is the very weight of the grain of a mustard-seed, even though it is in (the heart of) rock, or (high above) in the heaven or (deep down) in the earth, Allah will bring it (to light); surely Allah is Knower of subtleties, Aware;
   

3. 89:9 وَثَمُودَ ٱلَّذِينَ جَابُوا۟ ٱلصَّخْرَ بِٱلْوَادِ

   And (with) Samood, who hewed out the rocks in the valley,