An American Trade Dollar? Cool. I understand that they were meant for trade Chinese goods. More interesting is that the ATD had 420 grains of silver rather than 416 grains as in the British, French, and Japanese Trade Dollars. An enticement to have the Chinese pass other Trade dollars in favor of the ATD.
I have a shipwrecked 1874 CC in my collection.

Thanks for the comment @pocketechange
!PIZZA