Are trade dollars the rarest coins in the United States?
Could you elaborate on the rarity of trade dollars in the United States coinage system? Are they indeed the most scarce or do other denominations or specific years within the trade dollar series stand out as even more rare? If trade dollars are not the rarest, could you provide an example of a coin or set of coins that is more difficult to find and why? Additionally, what factors contribute to the rarity of a coin, such as mintage numbers, condition, or historical significance?