Can anyone tell me who may have made these glasses, or what kind of glass they are made of?

I bought these four pieces of glassware at an auction sale last weekend. They are each very thin glass with a hobnail pattern on them; however, the hobnail is small with rounded top and was pressed from the inside-you can feel the indentations. There are air bubbles on the foot. I was told they are flutes. Each is 10 inches tall. No marks on base. What kind of glass are they? Pale blue green color, like old soda bottles. My grandkids like fancy glasses to drink milkshakes/KoolAid/ice cream sundaes out of, so I buy them occasionally. If these are old, though, I’d like to know if they are vintage/antique and worth anything before I serve them ice cream in them and see one broken on the kitchen floor! Here is a photo-I hope it is clickable!:
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