hadith
3337
۞
Imam al-Kazim (AS) was once asked about gypsum that is burnt along with dried excrement and bone ash, and then used to plaster a mosque, and whether prostration on such plaster is allowed. He replied, ‘Verily water and fire [from the kilning process] have purified it.
الإمامُ الكاظمُ (عَلَيهِ الّسَلامُ) ـ لمّا سُئلَ عنِ الجِصِّ يُوقَدُ عَلَيهِ بِالعذَرَةِ وعِظامِ المَوتى ثُمَّ يُجَصَّصُ بِهِ المَسجِدُ ، أيُسجَدُ عَلَيهِ ؟ ـ: إنَّ الماءَ وَالنّارَ قَد طَهَّراهُ.