^ The “Single 9” Pond: South Africa's rarest gold coin. 4insure.us Retrieved on ^ Rare Coins – Heritage Auctions. 4insure.us 7 of the most valuable coins in the world · 1. The Flowing Hair Silver Dollar · 2. The Brasher Doubloon · 3. The Fugio cent · 4. The. The NGC World Coin Price Guide is a complete catalog of values for World coins from to date, created by NGC and NumisMaster price guide pages.