Thank you Chopin-liszt & flying free.
Chopin-liszt I prefer mine too

I love its tiny waist. Interesting they could date even earlier than mid 1800, and that they're mould blown, I always thought it was hand blown.
Flying free, I tried photographing it against a white background but it didn't show up detail nearly so well as against black.
It has a lot of bubbles but doesn't appear to be made up of bubbles like pulegoso.
It does have an odd grainy appearance though, difficult to tell if they're tiny bubbles or not.
I know it's hard to tell differences from a photo but it appears that mine is greyer with a streaky, 'waxy' look, which were the reasons it was suggested to be alabaster glass.