Question: How does one pay Zakaah on jewellery that is not simply gold but is gold with precious stone inlays? Does one also include the weight of those stones since it would be very difficult to remove the gold and weigh it by itself?
Response: Gold is the thing upon which Zakaah must be paid, even if it is simply for wearing. As for the precious stones, such as pearls, diamonds and so forth, there is no Zakaah on them. If a necklace, for example, has both gold and these other stones, the woman, her husband or guardian then must ponder the matter and try to estimate the amount of gold or give it to an expert to estimate it. It is sufficient to be fairly certain about the matter [and one need not be exact]. If the amount of the nisaab is reached, Zakaah must be paid. The nisaab is twenty mithqaals.. which is ninety-two grams. The Zakaah is to be paid every year [once a year]. The amount is 2.5%. For example, on one thousand, a person pays twenty-five. This is the correct opinion among the views of the scholars. If the jewellery is for business purposes, then one pays Zakaah on all of it, including pearls and diamonds, according to their [market] value, which is the same with all types of merchandise goods. This is the opinion of the majority of the scholars.
Shaykh Ibn Baaz
Fataawa al-Mar.ah