Prayer: The Preferred Materials for Sajdah
Practical Laws of Islam as per the teachings of Ayatullah Sistani
Ruling 1069
The best thing on which to perform sajdah is the turbah of His Eminence Sayyid al-Shuhadāʾ [Imam al-Ḥusayn] (ʿA), and after that, earth, then stone, and then grass.