Absolutely NOT IoWSG, they're far more delicate. It might be Mdina, but I can't swear to it. I would normally consider Gozo (or Wedgwood) for a big mushroom with a clear casing that extends beyond the colours in this way - but this seems to be a smaller one and is not typical Gozo colours. I'd say Mdina, was most likely, if pushed for an answer.
I do have a Gozo mushroom - the top is much flatter.
It has to be said I'm a bit random with the origins of my glass mushrooms.
(But I'm highly specific about the kind I eat!)