The Australian ten-ounce platinum piece (abbreviated as 10oz and designated with Pt for "Platinum") is a very large bullion coin format. Uniquely, in Australia there are two mints 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.
Both mints endeavour to create coins with attractive designs, and to introduce new designs and themes often, in order to raise the numismatic value of the coins over the value of previous metal used.
The overall weight of the coins is slightly over ten ounces, so as (accounting for the purity of the alloy) to have exactly 10 oz of platinum content. | 
