I'm pretty sure this is Italian. It's quite large and a real joy to own. The spots or "stains" are encased deep within the glass and not on the surface. The bottom is polished and has quite a few nicks. I just wanted to get an opinion from anyone who is familiar with Italian glass, but specifically Bianconi's work. I've seen some items that were signed "Venini" and attributed to Bianconi that look vaguely similar to this that are referred to as "con macchie". I was wanting to know if Bianconi always signed his pieces?