Larger size for today's business cards, this is a stunning example of mother of pearl souvenir, each diamond panel engraved and rich with natural shimmer of color. You can see this one tints between pink and green, or blues depending upon the light and reflecting surroundings. That's just the natural pearlescent of the old material. This size and type would have been from Napoleon III era to perhaps as late and 1900. Mid to late Victorian era. I only rarely see one so complete, or so lively in color. The shell is white, off-white, but the nacre or surface pearlescent reflective capacity is an entire rainbows light hits it from angles.
Very good to excellent condition for age and type, almost never find one this nice. Not a single bit of it missing nor chipped. I see 2 pieces have natural flaw, and 1 of the half-diamond triangles to top of one side might be a replacement. One panel has a 2mm hairline at corner but is not missing anything. You really have to search this one for The clasp and hinge at tightly set and working perfectly well.