Strange Item

[AndyLees]

I am trying to identify an object that I have in my posession; perhaps you could help.

It is about 5 inches high, egg shaped and made of a heavy pot or a mix of pot and metal. It is entirely glazed. The possible metal parts are 5 green coloured ridges which start at the top (or maybe the bottom if I have it upside down) and go to the bottom. There is a finger sized hole at one end. It is white with green ridges. It has no markings but the green reidges do have some pitting on them.

Any suggestions?

Andy