Sovereign sorting machine, 1906

Every sovereign blank made at The Perth Mint was weighed using one of these automatic balance machines before being minted into circulating currency. If a blank was too heavy or too light, it was rejected and melted down.

The Coinage Act of 1816 set strict standards for the manufacture of sovereigns which are still followed today. The precise weight of a freshly minted gold sovereign is 7.98 grams. 0.66 grams of this is copper, to increase the durability of the coin, and the remaining 7.32 grams is 22 carat gold. When sovereigns were used as circulating currency this amount of gold was worth exactly one pound sterling. Sovereigns were literally worth their weight in gold!