I say, and with God's success: You must pay its zakat if it reaches the nisab, and it is not a condition for the gold to be pure for zakat to be obligatory on it; it is sufficient for it to be mostly gold, because the majority has the ruling of the whole. Gold of 14 carats has gold predominating over other metals, as its gold content is 575 per thousand, which is more than half. The same ruling applies if the gold is of 18, 21, 22, or 24 carats. The criterion in this matter is that whatever is mostly gold takes the ruling of gold in terms of the obligation to pay its zakat in full. However, if it is equal to other metals at a ratio of 50%, there is a difference of opinion regarding the obligation of its zakat, and the preferred view is to require it as a precaution. As for if the gold is predominant, it is not subject to the zakat of gold, but rather it is treated as merchandise. As mentioned in Al-Tanweer by Al-Tamurtashi 2: 32, and God knows best.