Majmu' al-Fatawa - Ibn Taimiya - (29/451)

He was also asked:

About exchanging silver for debased silver in unequal quantities.

He replied:

If the amount of pure silver in one is equal to the amount of pure silver in the other, and that silver is what is sought while the copper is lost, and this amount has been determined through careful estimation and judgment, then this is permissible according to one of the two scholarly opinions.

Likewise, if the unalloyed silver exceeds the silver contained in the debased silver by a small amount corresponding to the copper, this is permissible according to the stronger of the two scholarly opinions. But if the silver contained in the debased silver exceeds the unalloyed silver, it is not permissible. Allah knows best.

He—may Allah Most High have mercy on him—was asked:

About exchanging Frankish akādīs coins for Islamic dirhams, knowing that the difference between them is slight and does not cover the cost of minting; indeed, these dirhams contain more silver. Is a hand-to-hand exchange between them permissible or not?

وَسُئِلَ: عَنْ بَيْعِ الْفِضَّةِ بِالْفِضَّةِ الْمَغْشُوشَةِ مُتَفَاضِلًا؟ . فَأَجَابَ: إذَا كَانَتْ الْفِضَّةُ الْخَالِصَةُ فِي أَحَدِهِمَا بِقِدْرِ الْفِضَّةِ الْخَالِصَةِ فِي الْأُخْرَى وَهِيَ الْمَقْصُودَةُ وَالنُّحَاسُ يَذْهَبُ. وَقَدْ عُلِمَ قَدْرُ ذَلِكَ بِالتَّحَرِّي وَالِاجْتِهَادِ. فَهَذَا يَجُوزُ فِي أَحَدِ قَوْلَيْ الْعُلَمَاءِ. وَكَذَلِكَ إذَا كَانَتْ الْفِضَّةُ الْمُفْرَدَةُ أَكْثَرَ مِنْ الْفِضَّةِ الْمَغْشُوشَةِ بِشَيْءٍ يَسِيرٍ بِقِدْرِ النُّحَاسِ: فَهَذَا يَجُوزُ فِي أَظْهَرِ قَوْلَيْ الْعُلَمَاءِ. وَأَمَّا إذَا كَانَتْ الْفِضَّةُ الْمَغْشُوشَةُ أَكْثَرَ مِنْ الْمُفْرَدَةِ فَإِنَّهُ لَا يَجُوزُ. وَاَللَّهُ أَعْلَمُ. وَسُئِلَ - رَحِمَهُ اللَّهُ تَعَالَى -: عَنْ بَيْعِ الأكاديس الْإِفْرِنْجِيَّةِ بِالدَّرَاهِمِ الْإِسْلَامِيَّةِ مَعَ الْعِلْمِ بِأَنَّ التَّفَاوُتَ بَيْنَهُمَا يَسِيرٌ لَا يَقُومُ بِمُؤْنَةِ الضَّرْبِ؛ بَلْ فِضَّةُ هَذِهِ الدَّرَاهِمِ أَكْثَرُ. هَلْ تَجُوزُ الْمُقَابَضَةُ بَيْنَهُمَا أَمْ لَا؟ .