1 Dollar - Elizabeth II 4th Portrait - Sister Cities - Silver Proof

Part of the Perth Mint's ongoing commemorative program marking Australia's international sister city relationships, this issue uses a lenticular lens element embedded in the coin's surface — a technique that shifts the visible image depending on viewing angle. The effect is achieved through a polymer insert bonded into a recessed field, a production method the Perth Mint developed and refined through the early 2010s for its novelty proof series. Lenticular coins of this type are prone to insert separation over time if stored in fluctuating humidity.