Phil writes: I have a gold coin from 1786 with the head of ‘CAROL III’ on it. What are its origins and is it valuable?
You’ll have to be more specific. There is more than one denomination in gold under Charles III of Spain. Identification includes the denomination: 1/2, 1, 2, 4 and 8 escudos, the Mint mark representing the place where the coin was made (several mints minted gold coins in both the New World and in Spain) and the assayer’s initials.
Generally gold coins from the period of Charles III are valuable and it is not always the largest coins that have the most value. For example the 1786 Seville 1/2 escudo assayer “C” can be worth as much as $4,000 in high grade circulated condition. vs a 1786 2 escudos from the Lima Mint that brings under $500.
Collectors are looking for high grade pieces and therefore those bring the highest prices. Of course, rarity is important also. Cleaned or polished pieces, unless they are extremely rare, are only suitable for jewelry and may only be worth a small premium over their gold bullion value.