✅Answer: Please pay attention to the following narrations:

1 عَنْ سَعْد بْن سَعْد قَالَ: سَأَلْتُ أَبَا الْحَسَنِ عَنِ الطِّينِ فَقَالَ أَكْلُ الطِّينِ حَرَامٌ مِثْلُ الْمَيْتَةِ وَ الدَّمِ وَ لَحْمِ الْخِنْزِيرِ إِلَّا طِينَ قبر الحسین فَإِنَّ فِيهِ شِفَاءً مِنْ كُلِّ دَاءٍ وَ أَمْناً مِنْ كُلِّ خَوْفٍ

📚Al-Kafi, Vol. 6, p. 266

Sa'd said: 'I asked Imam Kadhim (peace be upon him) about clay (or earth).' The Imam said: 'Eating clay is unlawful like carrion, blood, and pork, except for the clay of the grave of Imam Hussein (peace be upon him), for in it there is healing for every sickness and security from every fear.'

2 عَنْ مُعَمَّرِ بْن خَلَّاد عَنْ أَبِي الْحَسَن قَال: قُلْتُ لَهُ مَا يَرْوِي النَّاسُ فِي أَكْلِ الطِّينِ وَ كَرَاهِيَتِهِ قَالَ إِنَّمَا ذَاكَ الْمَبْلُولُ وَ ذَاكَ الْمَدَرُ.

📚Al-Kafi, Vol. 6, p. 266

Muammar said: 'I said to Imam Kadhim (peace be upon him): 'What do people narrate about eating clay and its dislike?' He said: 'Indeed, it is both wet with water and also hard clay (clod).'

3 عَنْ أَبِي جعفر قَالَ: إِنَّ التَّمَنِّيَ عَمَلُ الْوَسْوَسَةِ وَ أَكْثَرُ مَكَايِدِ الشَّيْطَانِ أَكْلُ الطِّينِ إِنَّ الطِّينَ يُورِثُ السُّقْمَ فِي الْجَسَدِ وَ يُهَيِّجُ الدَّاءَ...

📚Al-Kafi, Vol. 6, p. 266

Imam Baqir (peace be upon him) said: 'Indeed, wishing (that) is the work of whispering (Satan) and the greatest of Satan's tricks is eating clay (or earth), and clay causes sickness in the body and incites bad pain.'

Obsessive thoughts

4 عَنْ عَبْدِ اللَّه قَالَ: أَكْلُ الطِّينِ يُورِثُ النِّفَاقَ

📚Al-Kafi, Vol. 6, p. 265

Imam Sadiq (peace be upon him) said: 'Eating clay (and earth) causes hypocrisy!'

5 عَنْ أَبِي عَبْدِ اللَّه أَنَّ عَلِيّاً قَالَ: مَنِ انْهَمَكَ فِي أَكْلِ الطِّينِ فَقَدْ شَرِكَ فِي دَمِ نَفْسِهِ.

Al-Kafi, Vol. 6, p. 265

Imam Sadiq (peace be upon him) said: 'Imam Ali (peace be upon him) said: 'Whoever exaggerates in eating clay (and earth) has shared in his own blood!''

6 هِشَامِ بْنِ سَالِمٍ عَنْ أَبِي عَبْدِ اللَّه قَالَ: إِنَّ اللَّهَ عَزَّ وَ جَلَ خَلَقَ آدَمَ مِنْ طِينٍ فَحَرَّمَ أَكْلَ الطِّينِ عَلَى ذُرِّيَّتِهِ

📚Al-Kafi, Vol. 6, p. 265

Imam Sadiq (peace be upon him) said: 'Indeed, Allah created Adam (peace be upon him) from clay, so He made eating clay (wet or dry) unlawful for his descendants.'

7 عَنْ جَعْفَرِ بْنِ مُحَمَّدٍ عَنْ آبَائِهِ فِي وَصِيَّةِ النَّبِيِّ لِعَلِيٍّ يَا عَلِيُّ ثَلَاثَةٌ مِنَ الْوَسْوَاسِ أَكْلُ الطِّينِ وَ تَقْلِيمُ الْأَظْفَارِ بِالْأَسْنَانِ وَ أَكْلُ اللِّحْيَةِ.

📚Al-Faqih, Vol. 4, p. 372

The Messenger of Allah (peace be upon him and his family) said in his will to Ali (peace be upon him): 'O Ali, three things are from obsessive whispering: eating clay (wet or dry), biting one's nails with the teeth, and eating one's beard.'

8 أَبي جعفرالباقر قال: مَنْ أَكَلَ الطِّينَ فَإِنَّهُ تَقَعُ الْحِكَّةُ فِي جَسَدِهِ و تُورِثُهُ الْبَوَاسِير و يُهَيِّجُ عَلَيْهِ دَاءالسُّوءِ و يَذْهَبُ بِالْقُوَّةِ مِنْ سَاقَيْهِ قَدَمَيْهِ و ما نَقَصَ مِنْ عَمَلِهِ فِيمَا بَيْنَهُ وَ بَيْنَ صِحَّتِهِ قَبْلَ أَنْ يَأْكُلَهُ حُوسِبَ عَلَيْه و عُذِّبَ بِهِ

📚Amali al-Saduq, p. 325

Imam Baqir (peace be upon him) said: 'Whoever eats clay (and earth), itchiness will fall upon his body, and it will cause hemorrhoids and it will incite bad pain in him and it will take the strength from his two shins, and he will be held accountable for what he loses from his deeds from the time of his health, before he ate it, and he will be punished for it!'

9 قَالَ أَبُو عَبْدِ اللَّهِ الطِّينُ حَرَامٌ كُلُّهُ كَلَحْمِ الْخِنْزِيرِ وَ مَنْ أَكَلَهُ ثُمَّ مَاتَ فيه (منه) لَمْ أُصَلِّ عَلَيْهِ

📚Al-Kafi, Vol. 6, p. 265

Imam Sadiq (peace be upon him) said: 'All clay is unlawful like pork, and I will not pray over someone who eats it and dies in it (or from it)!'

✅What is strongly condemned in the above narrations is the eating of 'tin,' meaning clay (and earth), and 'madar,' meaning clod, which is earth that has been mixed with water and becomes clay, whether it is moist, dry, or in the form of soil.

✅The element of iron or zinc that is extracted from iron ore or zinc ore cannot be considered to fall under the terms used in the above narrations, and if there is no other problem with it from other dimensions, such as the fear of wastefulness due to it being harmful, then there is no prohibition from the aspect of the unlawfulness of eating clay (or earth).

✅Eating the soil and clay from the grave of Imam Hussein (peace be upon him) for healing has been exempted, though it also has important limits that are mentioned in their proper place.