Question:
If there is a difference in the value of the Nisaab, can we just accept the Nisaab of gold or do we have a choice?
Answer:
If one’s wealth has reach any one of the Nisaab, then that Nisaab would be maintained (whether gold or silver). On the other hand, if the savings have reached both Nisaab, then that Nisaab would be maintained which is beneficial to the poor and needy. i.e. the Nisaab that is less.
(Radul Mukhtar, Vol.2, Pg.299 / Hidaya, Vol.1, Pg.196)
And Allah knows best
Mufti Waseem Khan