Glass Bowl

I found this at the Sallies yesterday, there is too much work been done to it to be a cheap Chinese department store piece. There has been a lot grinding done on the flat part of the plate, the 3 inclusions look like Pau shell (abalone), all the colours are glass not paint and the edges are very rough (not what you would find in a retail store, someone might cut themselves). I think this sort of thing is called slump glass and is made using a kiln. 210mm x 210mm x 40mm. Any ideas?