Peace be upon you. My mother owns some jewelry which has reached the nisab (legal threshold), but she wears it at weddings. Does she have to pay zakat on it, and (if so,) how much?

In the name of Allah, the Most Merciful, the Grantor of Mercy

All praise is due to Allah, alone, and may peace and blessings be upon the one after whom there is no other prophet.
 

May the peace, mercy, and blessings of Allah be upon you, also.

Dr. Salah al-Sawy has a book, Al-Wajiz fil-Zakah (The Essential Book on Zakah). I will quote the following from it for you (with slight alteration):

Zakat on jewelry

In relation to gold and silver jewelry for women, there is a difference of opinion among the people of knowledge, since the material it is made of is almost like money. It is also due to the consideration that the craftsmanship and handiwork which has gone into it makes it similar to anything else taken from "merchandise prepared for trade" [a category on which zakat must be paid] for personal benefit and usage. For that reason, there is a difference of opinion amongst the people of knowledge on the issue of women's jewelry:

-Some of them proclaimed it absolutely obligatory for zakat to be paid on women's jewelry. This is the Hanafi madhhab and it is related from Sa`id ibn al-Musayyib. The majority, however, were of the opinion that it is not obligatory to pay zakat on jewelry as long as it has been used for adornment and it is not being used for acquisition and saving. Among the evidence for that is the following:

- That the basic principle is lack of religious obligation [in the absence of specific evidence], and no clear, authentic ahadith have been related to us regarding this principle.

- That zakat is obligatory on growing wealth or wealth prepared for growth, and jewelry is exempt from this category by virtue of being used lawfully.

- The stance that has been authentically related from many of the Companions that zakat is not obligatory on women's jewelry, for it has been narrated on the authority of Aishah that she used to follow her nieces (her brother's daughters) during her pilgrimage and they were wearing jewelry upon which they did not pay zakat. It has been related from Abdullah ibn Umar that he used to adorn his daughters and female servants with gold and then he did not pay zakat on their jewelry. Of course, his sister was Hafsa, one of the Mothers of the Believers [the Prophet's wives], and the ruling on that could not have been unknown to someone of her status. The ruling that zakat is not obligatory on jewelry was also related on the authority of Jabir ibn Abdullah, Asma' bint Abi Bakr and others, which indicates that this was widespread among the Companions, such that when `Amrah, one of Aishah's orphan girls [whom she was fostering], was asked about zakat on jewelry, she said, "I have not seen anyone pay it."

- It appears to us after this presentation of the evidence of both sides that the opinion that it is not obligatory to pay zakat on jewelry is the more evident one, because zakat is obligatory on wealth that grows or is liable to grow, so that the principle wealth remains and the zakat is paid from the surplus income, and women's jewelry is not of that sort. That is also why the home which is lived in and the animal (or vehicle) that is ridden are exempt. Likewise, work animals (or vehicles) are exempt from zakat, since they have been diverted from the field of growth to the field of benefit. As for jewelry which is kept for acquisition and savings, there is no difference of opinion that it is obligatory to pay zakat on any jewelry kept for the purpose of collection and as savings to help in times of hardship, which are not for regular use.

- Sa`id ibn al-Musayyib said, "Jewelry which is worn and used is not subject to zakat. If it is not worn or used, then it is subject to zakat."

- Imam Malik said, "Whoever has nuggets and jewelry made of gold or silver and does not use them for wearing, he is obliged to pay zakat on them every year.

- Imam al-Nawawi said, "Our scholars [of the Shafi`i madhhab] said, 'If jewelry is kept without the intent to use it in any unlawful, disliked or allowable way, but rather, the intent is to hoard and collect it, the correct stance is that it is obligatory to pay zakat on it, and this is the absolute decision of the majority. (Al-Majmoo` 6/36)

- Finally, zakat must be paid on any jewelry upon which it is obligatory in the same amount as the zakat on money: 2.5% (a quarter tithe). It bears the same ruling as gold, silver and all other forms of currency.

And Allah the Exalted knows best.