The Australian two ounces silver piece (abbreviated as 2 oz and designated with Ag for "silver") is normally 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 Koala series by the Perth Mint comes in several sizes and compositions:
- 5 oz gold proof, 2 oz gold proof high relief, 1 oz gold proof high relief ("numismatic"), 1/4 oz gold proof and 1/10 oz gold proof;
- 1 kg silver proof, 5 oz silver proof, 2 oz silver proof antique ("numismatic"), 1 oz silver proof high relief ("numismatic") and 1 oz silver bullion.
The reverse design changes every year, always featuring a koala - one of the most famous and distinctive animals native to Australia; the design of the two-ounce piece differs from that of the rest of the coins for the year, and has an antique finish and high relief; the Mint calls it a "numismatic" product and not bullion.
The silver two-ounce coins have a face value of 2 dollars, but this is only symbolic - as the bullion value of their precious metal content is much higher. The overall weight is slightly more than two ounces, so that the pure silver content is exactly 2.000 ASW (troy ounce Absolute Silver Weight). | 
