1977 Cook Islands $5 Silver Proof Coin FDC Wildlife and Conservation Day #23/100

1977 Cook Islands $5 Silver Proof Coin FDC Wildlife and Conservation Day #23/100Wildlife and Conservation Day. And the discovery of the Atiu Swiftlet, a unique bird species found only in the Cook Islands. Only 100 silver proof covers were issued worldwide, making this one of the rarest of all Cook Islands philatelic-numismatic covers. Wildlife and Conservation Day / Atiu Swiftlet Bird. 50% Silver, 50% Copper. 27.97 g approx. 0.45 troy oz total weight. 13.99 g (? 0.45 × 0.50) = 0.45 × 0.925? 0.45? No?? 0.45 troy oz × 0.5 = 0.225 troy oz pure silver (7.0 g). Queen Elizabeth