The one dollar coin denomination (written as $1) was introduced in Australia in 1984, replacing the earlier banknotes. The original reverse design by Stuart Devlin on circulating coins has not been changed since its introduction. The denomination is also often used to issue circulating commemorative coins with various reverses.
Apart from the circulating coinage, both the Royal Australian Mint and the Perth Mint have extensive programs issuing $1 coins for collectors (Non-Circulating Legal Tender, or NCLT). The Perth Mint uses this larger format for its $1 coins which is not compatible with the regular circulation coinage. The coins are not issued "loose" but are usually in a presentation card, or in a Philatelic Numismatic Cover (PNC). | 
