Handmade Metal Snuff Bottle? What is this thing?

This bottle came from a thrift store. It's not in the greatest condition, it's pretty rusted on the bottom and inside. It's only about 5" tall. It looks handmade but it's obvious that the craftsman was pretty skilled.
What could it possibly have been used for, and how old (even approximately) can it be? I looked at snuff bottles on the internet, but found nothing similar. I'm not even sure what category to post it in.
Any ideas are appreciated!