10 Dollars - Elizabeth II 4th Portrait - Koala - Silver Bullion Coin

Australia's silver Koala series, produced by the Perth Mint, changes its reverse design annually — a deliberate policy introduced to discourage melting and encourage collector retention. The 2013 issue belongs to the 10-ounce tier, which occupies an awkward commercial position: too heavy for most stacking programs, too common for serious numismatic collections, leaving it largely in the hands of mid-range bullion investors.

Ian Rank-Broadley's fourth portrait of Elizabeth II, adopted by the Perth Mint in 1999, appears here in its final sustained years of use before Jody Clark's effigy was phased in from 2015 onward.