Nice old piece. I have several of these. This is an egg coddler. It is porcelain and is in excellent condition.

No chips or cracks. 

It is 4 3/4” tall to the top of the handle, lid spins on an off and tightens nicely. Slight wear on the threads of the top but opens and closes freely. 

The base is 1 7/8” and it widens from there or bellies out.