Is zakat obligatory on 104.25 ounces of worn silver that has not had zakat paid on it for 18 years, and what is the amount of zakat due for this period?

The nisab (minimum taxable amount) for silver is 595 grams. If the uqiyah (ounce) intended is the well-known silver ounce, which is estimated at forty dirhams, then this amount greatly exceeds the nisab. If it is intended for wear and adornment, there is no zakat due on it, according to the more preponderant opinion, though paying zakat on it is more cautious. However, if it is for savings, then zakat is obligatory on it for the past years, and the amount due is a quarter of a tenth (2.5%).