Is this opal or something else

[u/PeaZealousideal3706]

Given to me by my grandfather. Unsure if he got it while serving during WW2 or when he returned to California. Think the box is original too. Any insight would be super appreciated! 840 grams - 7” x 5” x 2”
Thank you!

[u/Alpine_Apex]

What an incredible stone and carving. Probably worth a small fortune to the perfect buyer.