Antique tortoise shell snuff boxes rarely look like the “tortoise” shell antiques that we encounter today. Attempts were rarely made to make the shell colors pop. Tortoise shells were used because they were cheap and very malleable. The snuff boxes still have a rectangular shape and they can still have silver inlays or painted scenes. Most of these snuff boxes date from 1660 to 1730. They were especially popular on the British Isles.
If you are looking at a snuff box that obviously looks like the orange and black tortoise shell we see today, then you should probably be suspicious about it.