I visited Broadfield House Glass Museum on Thursday, while I was there I discovered what this little 'vase' was designed for. A couple of examples have been on the message board before (I have since discovered) so no doubt this won't keep people guessing for long.
This example is made with Uranium glass and stands 8cm (a little over three inches) tall, the rim is about 2.5cm (one inch) in diameter. The rim is ground and polished and there is some waterstaining on the inside. Faint vertical optic ribbing is also apparent but hard to see in my photos.
Sorry, no prizes for correct answers.

John