Not to hi-jack the thread, but here's another, much larger tumbler. It measures 4 1/8" large. The comparison is instructive. Quality is poor, muddy (lacking the clarity of the other posted pieces) and it is full of tiny dark inclusions, which I'm assuming are sand. The quality of execution, however, is similar to finer Toso/AVEM pieces. Thin construction, similar pontil. I have no idea who made it. If memory serves, I purchased it at an estate sale for something like $15-20. Probably a mistake, but it's not the end of the world.
Charles