100 Dollars - Elizabeth II 4th Portrait - Australian Nugget - Gold Bullion Coin

The Australian Nugget series shifted its reverse design annually beginning in 1989, a deliberate marketing strategy to drive collector demand alongside bullion demand — a model Perth Mint borrowed directly from the success of the Canadian Maple Leaf's static design, then deliberately inverted. By 2003, the series had established a secondary market specifically around date-collecting, unusual for a pure bullion product.

The "pad printed" composition notation flags a surface enhancement technique applied to select issues, where ink or color is transferred onto the coin's face under pressure — a finishing method that complicates melt valuation and remains controversial among strict bullion purists.