How do I get this effect?

[Jessicak]

Hi guys,

I'm hoping someone will be able to help me identify this glaze. I've never seen anything like it before, and I love the way it looks almost like the iris of an eye. I first thought that this effect was just the glaze running, but this seems to be on a pretty flat plate so I'm not sure that is the case

Does anyone know what this type of glaze is called or how to recreate the effect? 

[Mark C.]

I cannot help you with that exact glaze but will add that its to think and has run down into what I refer to as broken windshield (thats a condition that makes that thick crazed unsafe for food use look

I'm guessing its a light cobalt glaze over porcelain clay body

applied way to thick or over fired take your choice same result

[Callie Beller Diesel]

I agree it’s probably a very overfired glaze that’s dissolving either a cobalt glaze or wash. Beautiful on decorative ware, but wildly impractical for cereal.