Conundrum

This is a wonderful piece of turned lignum vitae from the first quarter of the 18th century. But what on earth was it used for?

It’s in two pieces. The conical goblet lifts off the base, revealing a small well carefully hollowed out to hold something – but what?

Drink something out of the conical beaker, and keep something small in the well in the base? Dice? Game counters? Was it for a drinking game?

No-one seems to know what it was made for, yet it was carefully and skillfully made, clearly for a specific purchase. Any ideas would be very welcome.