In the 1870's and 1880's it was a common practice for a young man to take a coin and have one side planed off smooth and then have his initials engraved upon it. This token of his love would then be offered to the object of his affection. If accepted it could or would be be seen as an sign of betrothal. (The concept of the diamond engagement ring is a modern creation of the DeBeers company as a method of increasing demand for diamonds.)
Other times the coins would be engraved with the initials of the children and used as bangles on bracelets or necklaces.
Engravings can range from simple and crude, to very fancy professional engraving with diamond cuts, inlays, and multilayering of gold and silver.