25 Dollars - Elizabeth II Princess Diana: 20th Anniversary

Cook Islands has issued commemorative silver rounds under royal warrant for decades, but this 2017 piece marks the twentieth anniversary of Diana's death in the Paris tunnel crash of August 31, 1997 — an event that triggered one of the most unusually intense public grief responses in modern British history, ultimately pressuring Buckingham Palace to break protocol and lower flags to half-mast. The 155-gram format places it firmly in the five-troy-ounce category, a weight class increasingly favored by Pacific island issuers targeting the bullion-collector crossover market in the mid-2010s.