فَإِنْ كَانَتِ النُّقُودُ مُخْتَلِفَةً فَالْبَيْعُ فَاسِدٌ إِلَّا أَنْ يُبَيِّنَ أَحَدَهَا.
Translation: If different currencies circulate without a clear prevailing one, the sale is irregular unless one currency is specified.
If several materially different currencies are plausible and none is dominant, a bare number does not identify the price.
Quduri calls the transaction fasid (irregular) in this case. Hanafi doctrine distinguishes fasid from batil, so the source’s precise legal label should be preserved.
For example, if “100” could mean 100 rupees or 100 dollars, the unit must be identified.