??
May we have some more pics of the inside, and the whole bottom (etc)?
I know we are just going by a photo here, so wondering IF we could have some more. I am wondering ( and just going to throw this out there ) based on the only 2 current pics we have......Might this be pottery? Raku?
The only reason why I am saying this is because I note a one blemish on the vase pic and it looks more like a blemish you might see on Pottery. Also

the signature on the bottom seems a bit too white in color to be glass ( doesn't it ) and more wide, and more carved like?? ?? ?? than one would expect to find in Glass. Again -- Just saying this based upon only 2 pics
I do not know......and maybe more pics will help. One time here myself (in the beginning) I thought a
piece of Glass was pottery......so it does happen. It has happened to others also, so anything is possible when only looking at a couple pics. May be wrong -- but this is a discussion board -- and never hurts to search all options.
(( Think we have Stone, and Soapstone, and other pottery pieces that looked so much like Glass in the past here on the board....... so it does happen.... ))So again, just throwing this to the wind.......
and I wear Glasses here.....LOL (getting old, old eyes )