Mystery Object in Macro

Took me a while to find a mystery object and then I remembered this little glass object purchased at the Kings Park Gallery Shop not long ago! It was not something I needed but wanted!! : ) 
Promised myself I wouldn’t buy things like this anymore but hey ho proving to have very weak will power!! : )
Possibly not too hard to guess its function?
Thanks to Jen for hosting TT this month, it’s been fun! : )x