Nice Koroit Opal Rough Chunk 560.5cts Crystal/Multicolour Core Fires Qld Australia

I have for sale a Nice Rough Koroit Opal Chunk, Specimen Rough from Queensland Australia. This one weighs 560.5cts and is 68x44x32mm.  Dark, Banded ironstone nut piece here with a very nice Gemmy Crystal/Milky Opal Core. It has a few thin veins around that but the focus on this one is that core,.,. not sure how far into this piece it goes, but its a thick chunk of material. Maybe slice it, to find the back edge, and get 2 Freeforms/Cabs from it. Or polish that top face and leave as a Superb Specimen piece,.,.  Thanks for looking,.,.,.