Does a small decrease in the minimum threshold (nisab) affect zakah?
Question

I own jewellery that surpasses the minimum threshold (nisab). Three months before the end of the zakah year I sold some of it, and its value fell below the minimum threshold by only a very small amount, a few grams. Then after that I bought some jewellery and now the zakah year has passed and it is more than the minimum threshold. How should I pay zakah on my jewellery this year?
Praise be to Allah.Firstly:
If the jewellery reaches the minimum threshold, which is eighty-five grams [of gold], and one full hijri year has passed, zakah must be paid on it. But it is stipulated that the individual must have owned the wealth that is subject to zakah for an entire year, so if it fell below the minimum threshold during the year, he should start counting a new zakah year. See the answer to question no. 99381.
Secondly:
If the shortfall was small, as mentioned in the question, or less than that, should he start counting a new zakah year, or should no attention be paid to a small shortfall?
An-Nawawi (may Allah have mercy on him) said: In order for zakah to become due on gold and silver, the individual must have owned it for a whole year, with no difference of scholarly opinion regarding that. So if he owned twenty mithqal for most of the year, then it fell below the minimum threshold, even by a small amount, then was topped up an hour later, the first zakah year was interrupted, and no zakah is due until a full year has passed from the time when it was topped up to the minimum threshold.
End quote from al-Majmu`, 5/491.
He also said:
If it fell below the minimum threshold by the weight of a grain or part of a grain, then no zakah is due, and there is no difference of opinion among us… This is our view, and it is the view of the majority of scholars. Malik said: If the two hundred [mithqals] of silver decrease by the weight of one or two grains and the like, this is something that people usually overlook, and zakah is still due.
End quote from al-Majmu`, 5/490.
In al-Kafi it says: … If the shortfall is slight, such as the weight of one or two grains, then the apparent meaning of the words of al-Khiraqi indicates that no zakah is due on it, because of the reports [meaning the hadiths which define the minimum threshold (nisab)].
Other companions of ours said that zakah is due on it, because this is not something noticeable, like being one or two hours short of the zakah year. End quote.
Shaykh Ibn `Uthaymin (may Allah have mercy on him) said: What appears to be the case is that the view of al-Khiraqi is the correct view. As long as Islamic teaching has specified the threshold, we should refer to that, because the value of the weight of one or two grains may be great, so the correct view is that the threshold is specific and is not an approximation.
End quote from Sharh al-Kafi.
To sum up: if the jewellery fell below the minimum threshold, even by a small amount, the zakah year was interrupted, and counting a new zakah year starts from when it first reached the minimum threshold a second time.
In such a case it is better to give zakah so as to avoid a matter concerning which the scholars differed, and some of them said that a small shortfall is of no significance.
And Allah knows best.