What if gold/silver has been mixed with other metals?
If there are impurities in gold/silver, then it will be checked whether the impurities are predominant in the gold/silver or not. If the impurities are less than gold/silver, it will not be considered and Zakaat has to be given on the whole. However, if the impurities are predominant in the gold/silver, then they will not be considered as gold/silver at all and the ruling will change. As mentioned in Al Bahr Ur Raaiq, Vol. 2, Pg. No. 397/398.