Natural thick Mother-of-Pearl 3½-inches wide.

All you would need to do is remove the clasp and stud pins and bond buckle hardware.

It has a perfect curvature like any other adult belt buckle

I have no idea how old it is, though 3½" is hard to find in solid and unlaminated MOP... and I seriously doubt you can find a real MOP belt buckle this size and in this condition...

How about $125 and shipped in a Priority Mail carton...? Unless you have something of interest to me in trade...