I am wondering g about the markings on this piece. I know it is a Crosby, Hunnewell and Morse piece. It has been in my family for a very long time.
This American company was apparently only in business, in Boston, from 1861-1863. The “900 FINE” marking indicates that it’s not quite up to sterling purity standard (.925), but is what’s often called “coin silver.” Coin silver is usually .800 to .900 purity.
As there’s no official U.S. standard for marking silver, the markings mean virtually nothing - they were just whatever the maker felt like using.
ETA: Something similar, though true sterling, and a bit fancier: