I don't know a lot about it. I think it is some kind of opal with geodes Inside. i can see 2 expose geode locations. But believe there are more due to the size of the stone
9"× 9" x 6"
An Opal Matrix "Geode", Modern
the specimen showing signs of some translucency and opal matrix internally, dimensions:
9"× 9" x 6".
Possibly of Canadian origin.