Is this a snuff bottle?

Hi All,
I came across this little piece the other day and I am wondering if it might be a snuff bottle? The shape seems a bit unusual but it appears to be made from horn and ivory. I've only been able to find one similiar piece; located on an auction site: http://www.liveauctioneers.com/item/17008916_chinese-rhinoceros-horn-snuff-bottle-w-ivory

They look very similar...both have thumb rings, but as I can only find the one similar bottle and mine won't open (don't want to force it too much)so I am just not sure...

Have you ever seen anything else like this? Any help would be appreciated!