This is a family bowl (from my husband's grandmother, who apparently had it from someone else in the family), and I've been trying for a bit to figure out what it is. I can't find a manufacturer's mark. The base looks like an extra piece attached (not very neatly) to the bowl, I've tried looking through it at a light but still can't find anything. It is about 5.5" high, 13" from corner to corner. Ideas appreciated, sorry if this is obvious I know nothing about glass.