This is a Massive Boulder Opal where the iron ions crystalized in giving similar shape to petrified wood
It is a gamble opal with potential, it can be seen multiple blues and purples between the iron veins.
You can either cut it or leave as mother nature did
This is a million years old specimen
Specifications:
Gemstone Type: Boulder Opal
Shape: Natural Rough
Color: Blue and petrified wood simulation
Size: 110 x 80 x 40 mm
Weight: 708 g or 3540ct
Origin: Quilpie - Queensland
The mother of the opals