Please help identify this glass maker.

Hello.
I found this at a thrift store.  I think it's a drinking glass, but maybe not.  Very dark amethyst glass or cased.  It's about 5" tall and 3" across, heavy (one pound!) and has this embossed stamp on the bottom which I thought might be a large "D" with a "B" inside or if I turn it sideways, it almost looks like a head of a cat with eyes inside.  Any ideas?

Thank you

This looks like a glass bottle mark (they sometimes make other items such as vases). Try one of those sites - here is one but there are many more https://glassbottlemarks.com/bottlemarks/