Mid century handblown vase or newer knockoff?

I just purchased these at a mid century consignment shop and the salesperson didn't have any information on the origin or age, I was hoping someone here could point me in the right direction?

They are approx. 12" tall and 5" wide at the widest point with 1" diameter rim at the top. They have very heavy clear glass bottoms with the rest of the vessel a smoke grey that lightens as the glass thins towards the top. They have no manufacturer markings at all that I can find. I really like them and would love to find out more about their origin.

Thanks in advance!

ikea it is...

Well I do like them irregardless so I guess that just means I overpaid for them

Are there some tell tale signs that one uses to determine this or is it just having a broad familiarity with the more sought after pieces from the era with most everything else being newer stuff from places like China and Poland? I would like to have something to look for next time I find myself trying to determine if a piece is worth the price.