Fiqh-us-Sunnah Volume 3, Zakaat and Fasting, Fiqh 3.013A.

Section : Zakah on Gold and Silver.

Says Allah concerning zakah on gold and silver: “…As for those who hoard treasures of gold and silver and do not spend them for the sake of Allah – warn them of grievous suffering [in the life to come]” [at-Taubah 34]. Thus, zakah is prescribed for gold and silver – whether they are in the form of coins, ingots, or dust – as long as the amount owned constitutes a nisab, a period of a year has passed, debts are settled, and/or basic needs satisfied from it.