A colleague at work showed me this plate today in the hope I could ID it. All he could tell me was it once belonged to his wife's great grandmother, a family that moved from Italy to Sao Paulo. It's now treated as a family heirloom as one of her surviving items. It is unlikely to date before 1930 from what I hear, and obviously it has no financial value.
It is about 7 inches across and my best guess was mid 20th century import. I thought it looked quite similar to Pasari Indonesian glass.
Any other ideas?