The bowls are fused glass, a different glass is used, cut decorated in layers and fused at high temperatures, for bowls it's then slumped in a mould. The colours sometimes change after firing, this purple started as dark blue, but I like the unexpected effect. I should have looked at the colour chart! The decorations are piped on like royal icing and melt into the glass.
This one is similar, in a four-bowled mould, the spots are glass fragments.
All in all a constructive term's work, one big piece to finish so watch out for it.