Unusual opal , maybe trace fossil?

[Vopros]

1 hour ago, Pixpaleosky said:

It seems to be several opal nobbies together.

You can see on this link a typical nobby : https://blackopaldirect.com/blog/rough-opal-nobbies-lightning-ridge/

 

You may contact the website owner who is a famous expert.

Yes, I watched his videos. He is more into jewelry than in fossils. I asked him anyway.

Maybe he will reply. However, I believe that it is rather unlikely that a few nobbies cemented together like that.

[Vopros]

And now I got a response, which states:

 

"You can upload your images by clicking on the link below. We will then give an informed opinion based on the images you provide and will answer any questions you have. There is a small cost for this service and we donate all money raised to an amazing charity."

 

The “small cost” is 25 USD. I’ve decided to pass on this.

[Vopros]

On 7/20/2024 at 6:56 AM, ynot said:

If the external shape of an opal is not preserved it is very hard to say what the piece started as.

I have been filming opalised wood and remembered your statement, ynot. Below are some microscopic images of cellular structure of the wood well preserved in opal. In fact it occurs quite often that the inner structure of bones, wood and other fossil are preserved beautifully in opals. When I showed a broken pease this lungfish tooth-plate to a paleontologist she told me what it was right away.

 

Edited August 3 by Vopros

[Vopros]

And now I got the response from Dr. Elisabeth Smith.

Dr Smith writes:

 

Hi Mila

Thanks for the inquiry and photographs, and please pardon my very slow response. I've examined your photographs carefully and studied the video many times.

This is a complex specimen that can't be explained easily. As I've said before, I'm not a geologist or geochemist. The following comments are tentative only, based on my knowledge of the unique geological materials of Lightning Ridge.

The whole piece has been heavily abraded and rounded in the agitator barrel (mining machinery), and it appears that the convex surfaces are further altered by shaping and polishing on the lapidary wheel.

The potch and opal components are typical of sedimentary claystones from certain opal-bearing levels at Lightning Ridge. Basically it's a chunk of coarse-grained sandstone embedded with opalised nodules.

The included objects are probably geochemical and diagenetic in origin. The ball-like clasts enclose concentric textures, fine reticulations, septarian patterns and curlicue lines that probably formed as a result of dessication, shrinkage and repeated episodes of silicification. It's tempting to interpret the rounded objects as pieces of waterworn animal bone with some of the internal microstructure preserved, and the cylindrical pieces as poorly-preserved wood fragments. However I think it's more likely that these are purely geochemical structures. 

None of this is certain but you definitely need a stronger microscope for your camera. There are no tracks or insect traces, your red/brown inclusion is probably iron or hollandite and the crystals are transparent opal that has shattered in the mining machinery. 

A very nice specimen all the same!

Best regards

Elizabeth

Australian Opal Centre

Lightning Ridge NSW Australia.

 

Then I asked if it looks as a coprolite.

Dr. Smith wrote:

 

Hi Mila

An interesting suggestion but there's no indication of separate particles inside the nodules. Coprolites are usually packed with shreds and shards of plant matter and other fine objects, usually with sharp edges. But I agree the total massed shape could be interpreted as coprolitic. By the way, it's much easier to interpret surface details when the object is dry.

Elizabeth.

 

[ynot]

22 hours ago, Vopros said:

. In fact it occurs quite often that the inner structure of bones, wood and other fossil are preserved beautifully in opals.

yes opal can make some excellent cellular preservation fossils , but I was speaking of the cast type of fossils that are the majority of fossil type from lightning ridge that I have seen.

[digit]

1 hour ago, Vopros said:

And now I got the response from Dr. Elisabeth Smith.

A very nice and well reasoned response. She seems like a good resource to use sparingly on only the most enigmatic of pieces (so as not to wear out your welcome). Nice to have access to a person with deep knowledge in the realm you are looking for answers.

 

 

Cheers.

 

-Ken