I love Mercs. They're one of the most beautiful coins ever minted imo.
I also love those old medals. I've found a few but only one really nice old one so far.
Yours is definitely a catholic medal that depicts the Virgin Mary but I can't read the inscription. Your pic won't enlarge. So I can't tell if that's Jesus on the back or one of the gazillion Saints; possibly St. Christopher. If you can tell me the inscription I may be able to help you.
It could be one of those combo medals. The front looks like the "Miraculous Medal" but the reverse is different.
Also, look to see if there is an inscription as to where it was made. My really nice one was made in France.
Your medal looks like a Mother Mary Visitation, I found one that has the date 1830 under Mother Mary's feet.
The medals with dates mark the years where Mother Mary is said to have appeared to the faithful.
Congrats also on the Mercury. It is truly a beautiful coin. The Mercury Dime and the Walking Liberty Half were
both designed by Adolf Weinman. Two of my favorites.