This is a mid-19th century Serpentine Toiletry Casket with Boulle style marquetry. The box has engraved brass and red turtleshell inlay on what looks like a mother-of-pearl background. However as you can see, the surface has many cracks that are typical of early cellulose nitrate plastic.
First I compared this plastic mother-of-pearl and real mother-of-pearl. Here you can clearly see the difference between the two materials, with the real mother-of-pearl showing characteristic iridescent interference colours (generated by thin layers of the mineral aragonite, a form of calcium carbonate.)