I see those tiny bubbles a lot in glassware (wineglasses, or stirrers for example), so I would assume it's an effect of the glass making process. Real handmade glass seems to often have even bigger bubbles than yours in it sometimes! A quick google search on glassmaking has a lot of tips on how to eliminate air bubbles from your piece, so I assume it's not a desired effect.


I wish I knew if it meant it was more likely to affect the strength of the glass, or just because it's not as pretty, hopefully someone else does!