Silver coin needs identifying

[Emperor Findus Cladius]

I have a silver coin, smaller than a dime, that I have no idea what it is. The obverse has what looks like a lady standing with a staff, and the words "FIRME Y FELIZ" on the left and "POR LA UNION" on the right. The reverse has some type of shield with a wreath on top, the date 1855 on bottom, and the words "PERUANA M M 20G M R" around the edge. Any ideas? Thanks. Sorry, dont have a camera.

 

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[PBK]

1855 half real from Peru. Inscriptions mean "Steady & Happy" and "For the Union." The M R should be M B; not sure, but I believe they're the mintmaster's initials.

 

[Emperor Findus Cladius]

Thanks, any idea if it has much value?

 

[PBK]

Maybe $7-10 in Fine condition.