Can you identify a charm depicting the Blessed Mother?

[Faithful12]

I found a piece of jewelry that may have been a charm on a necklace. In the center is a statue of Mary. Surrounding the statue are these words “Mary, conceived without sin, pray for us who have recourse to thee.” Below that it looks like the numbers 1830. On the back, it looked like a picture of three intertwined crosses. Can you tell me the story surrounding it?

 

[Michelle_Arnold]

It’s a Miraculous Medal, the design for which was given to St. Catherine Laboure in 1830.