Can you identified what is this rock (fossil?)

Could be.
If farmerman checks in, perhaps he can take a look at it.

It certainly looks like petrified wood, but hard to say for sure from a photo. How detailed are the edges?

The edge is a little detail. This is the best picture I can take with my phone.

http://www.hostingpics.net/viewer.php?id=787528strangerock2.jpg

Sorry, it's still impossible to tell whether it's sedimentary rock or petrified wood.

You really need to look closely at the grain and see if there are any obvious organic/wood formations. Basically you need some feature which distinguishes it from sedimentary rock or petrified wood.

Yes Kozeg it sure looks like pet wood

How can you say that, Dale?

It has nothing to do with Trincomali wood (petwood) aka Berrya Ammonilla..

Be precise and forget abbreviations..

Thanks for clarifying.
I thought he was suggesting a leash for it.

I wouldn't be surprised if he did...

With utmost aplomb, Tim

Oops Tim that's on one me

...the one time I forgot the dot

Its petrified wood. Its a type that is a common opal infill. Its quite common from Jurassic nd Cretaceous beds of the North American west and Africa . Some of the beds, where hot water stayed and penetrated , fire opals are formed . Its quite common to have this dull massive woodlike rock showing layers and rings and then, BAM, youd see whole lenses of fire opals in the wood.

Id look round the same area because that wood structure can houae some really nice gem quality opal if there was enough of a hydrothermal contact zone.