10 Dollars - Elizabeth II Posthumous, Lighthouse of Alexandria

The geometry here is immediately suspicious: 45 mm diameter for 0.31 g of gold is physically impossible as a solid coin. This is almost certainly a large base-metal piece with a small gold inlay or gold-plated insert — a format aggressively marketed by private minting houses operating under Pacific island licensing agreements. Solomon Islands has issued hundreds of such pieces since the 2010s, the vast majority produced by the Coin Invest Trust or affiliated European mints with nominal Central Bank authorization.

The Lighthouse of Alexandria series fits a well-worn commercial pattern. Legal tender face value exists on paper only.