Is any a bone?

[Vopros]

Here are two opals from Lightning Ridge , Australia.

They are wet (not my pictures), and no bone structure is seen,

but just by looking at the shape, what do you think?

[Fossildude19]

Doesn't look like bone to me.

[Mike from North Queensland]

There will be no bone structure as the opal matrix is a replacement of the original bone in the void left after it dissolves. 

[Vopros]

1 hour ago, Mike from North Queensland said:

There will be no bone structure as the opal matrix is a replacement of the original bone in the void left after it dissolves. 

Not always. Many opal bones preserve the structure perfectly. 

[Fossildude19]

Regardless. I am doubtful this is any kind of bone.

[rodrex]

On 1/30/2024 at 3:55 AM, Mike from North Queensland said:

There will be no bone structure as the opal matrix is a replacement of the original bone in the void left after it dissolves. 

Not in all opal fossils, most still have bone microstructure.

 

Ive attached some examples of opal replacement bone below, where you can see microstructure.

[Ludwigia]

One can only say, based on a couple of pictures, what one "thinks", which really isn't any proper help if you want to get to a firm ID. The best chance in my opinion is to get such pieces scientifically analyzed from experts.