little 'manicure tool' (?) with ivory (?) handle

Does anybody know what this tiny little 'tool' really is??

I'm guessing maybe once part of a "manicure set" since I can't think of anything else that makes the slightest bit of sense... but then again, I don't actually know the slightest thing about "manicure sets", so... ???

As seen, its round handle is a little shy of 3" long and about 1/4" wide. The metal piece at its end actually unscrews/loosens, which lets the flat-diamond-pointed 'blade' thing slide in and out about an inch or so.

I suspect the handle could be made of ivory, since it is not perfectly uniform in shape, does appear to have the slightest bit of 'grain' to it, and has exactly the right "feel". But once more, I don't really know for sure...??

If anybody recognizes it, I'd love to hear your thoughts!