The Australian one ounce silver piece (abbreviated as 1 oz and designated with Ag for "silver") is a bullion coin format. Uniquely, in Australia there are two mints independently authorised to strike legal tender: the Royal Australian Mint (which also makes the country's circulating coinage) and the Perth Mint which only makes collector and bullion coins, as well as other bullion products.
The Australian Swan series has been issued by the Perth Mint since 2017, in silver and gold formats.
Swans of the black feathered variety (Cygnus atratus) are graceful inhabitants of the southeast and southwest regions of Australia where they live and breed in estuaries, inlets and other wetland environments. Residents of the Swan River, which takes its European name from their presence, black swans figure in ancient Aboriginal lore and were quickly adopted by European settlers as the bird emblem of Western Australia.
The reverse design changes every year, always featuring a swan. The overall weight of the coin is slightly more than an ounce, so that the pure silver content is exactly 1.000 ASW (troy ounce Absolute Silver Weight). | 
