Topic: control bubble paperweight cased blue blob and lug on top

[scavo]

shares some similarites with this 'murano' ashtray http://www.legacyantiques.co.uk/index.php/glass/venetian-glass-murano/ashtrays/murano-glass-blue-encased-ashtray-with-enclosed-bubbles.html
Also similar to a Czech vase I have with bubbles around a blue blob
Pontil is deep but not highly polished. Some scratches on the base suggesting some age.

Can anyone help?