How can the monetary nisab be calculated based on the value of 85 grams of gold or 595 grams of silver, while Sheikh Al-Shinqiti considered it usury (riba) to determine the value of 595 grams of silver with paper currency, because the paper riyal originally corresponded to a specific weight of silver, and therefore, the exchange of silver for silver requires equality and immediate possession?

The fatwa adopted by jurisprudential councils and contemporary scholars is that the nisab (threshold) for currencies is estimated by the value of the nisab for gold or silver, taking into consideration what is more beneficial for the poor.

In the fatwas of the Permanent Committee for Scholarly Research and Ifta', it states: "The amount of the nisab for zakat on the dollar and other paper currencies is what is equivalent to the value of twenty mithqals of gold or one hundred and forty mithqals of silver, and this should be what is more beneficial for the poor."

It also states: "One quarter of a tenth of the paper currency owned must be given as zakat, in the form of paper currency, if it reaches a nisab equivalent to one hundred and forty mithqals of silver or twenty mithqals of gold, and a full year has passed on it."