Wood opal is a form of petrified wood which has developed an opalescent sheen or, more rarely, where the wood has been completely replaced by opal. Other names for this opalized sheen-like wood are opalized wood and opalized petrified wood. Wikipedia.org

Opal is the product of seasonal rains that drenched dry ground in regions such as Australia’s semi-desert “outback.” The showers soaked deep into ancient underground rock, carrying dissolved silica (a compound of silicon and oxygen) downward. Gia.edu

So this piece of wood was affected by water and this is the result over some time less than about 6,024 years since the beginning of all Creation.

Up until fairly recently, nearly all printings of the King James Bible included dates in the marginal notes which helped place Biblical events in their chronological context. Using this as a guide we can see that "God created the heaven and the earth" in 4004 b.c.; the Flood covered the Earth in 2348 b.c.; the Exodus occurred in 1491 b.c.; David became King of Israel in 1056 b.c.; and the Nation of Judah was carried into captivity in 593 b.c. Obviously, the numbers are helpful in understanding the sequence and timing of events, but where did they come from, and are they reliable? Icr.org Dr. John D. Morris, Ph D. Dec 1, 2003.

Here is the most beautiful piece of wood opal I have ever found, a 39.80Ct Story Opalized Wood Pear Shape probably from Indonesia. I Love the way this stone paints a scene from nature. This Stone was examined by the Gem lab and called Opalized Wood and refractive index tested Opal. This stone is sold.