What Can and Cannot Be Used for Prostration
Man Lā Yaḥḍuruh al-Faqīh|Volume 1|Book 1|Chapter 41
وَ سَأَلَ مُعَاوِيَةُ بْنُ عَمَّارٍ أَبَا عَبْدِ اَللَّهِ عَلَيْهِ اَلسَّلاَمُ: عَنِ اَلصَّلاَةِ عَلَى اَلْقَارِ فَقَالَ «لاَ بَأْسَ بِهِ.
Muawiya ibn Ammar asked Imam Jafar ibn Muhammad Al-Sadiq عليه السلام about praying on qār (bitumen or tar). The Imam said: "There is no issue with it”.
- Ṣaḥīḥ al-Faqīh