ISLE OF MAN. Platinum Decimal Coin Set (6 Pieces), 1975. Elizabeth II. GEM PROOF. KM-19b-24b. APtW: 2.929 oz. A stunning set of coinage from a small mintage of just 600 pieces. Housed in the original case of issue with a notation from Andrew Portale indicating that this is the official 1975 Platinum Isle of Man set. From the Liberty Collection.