I know that these can be very difficult to attribute, but I recently got some pieces at a garage sale of some people that owned a shop many years ago and had a very large quantity of Italian glass pieces for sale. The glass had been stored in boxes for around 30 years or so.... I purchased 8, and have sold most of them, but I kept 4 pieces. I am going to post three of them to see if anyone has any thoughts. I have kept the three as they are exceptionally well executed and in person are a definite grade above the average generic Murano items I see all the time.
This is the second piece. The coloration of the glass is much closer to a light root beer color than anything else. It is a little different color than I have come across before, and I have seen quite a bit of this type of glass. The aventurine areas are separated into kind of "panels, defined by straight lines in the aventurine patterns in the glass. The aventurine is more pronounced than the image shows. It was very difficult to get an good pic of it. Again like the other, it is is extremely well executed, and not your average aventurine bowl.
Size is approx 6 x 5 inches and 2 inches high.
Bottom is polished and flat with appropriate age wear.