French Silver 'Grinder'

I aquired this today as a French ‘Sugar Caster’. The silver is marked for the late 19thC Parisienne silversmith Jules Marie.
However, obviously not a caster and its light mechanics prevent its use as grinder for rock type sugar/pepper or rock salt (tried it).
The garnet knop is turned to perform the grinding, but would like to know what it could be possibly used for
All ideas welcome.
Thanks in advance
John
Grinder.jpg
Top.jpg
Sugar.jpg

It seems my 9 year old neice should contribute here.
When I showed this to her she immediately said, " What if you press down the red stone?"
I shook with disbelief as the inner base eased out to release the contents!
Suffice to say it dispenses caster sugar.
I’ll stick to the day job :confused:
Regards
John