The Australian one kilo gold piece (abbreviated as 1 kg and designated with Au for "gold") is a 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.
This massive one kilogram gold coin is part of the long-running Australian Kangaroo bullion coin series by the Perth Mint.
The Mint says about it:
No wildlife symbol more powerfully equates with Australia than our beloved kangaroo. In 2021, the marsupial famed for the way it bounds on elongated hind legs, is portrayed on Australian Kangaroo silver bullion coins by a representation of Stuart Devlin’s classic "red kangaroo" design. Larger than eastern and western greys, the red kangaroo is Australia’s largest native mammal. Superbly adapted to arid environments, it lives throughout central regions of the continent.