Opalized yabby button(crayfish gastrolith)? ..or something else?

[katherine1977]

This came in a parcel of opal from Lightning Ridge. I have cut the bottom and a little of the side to be able to see inside better. The smaller opalized top portion is 8x10mm, the bottom opalized portion is 12x10mm.

I have been told this may be a yabby button, however I’m not sure because all the photos I’ve seen of yabby buttons don’t look a whole lot like this.

I appreciate any feedback, and feel free to ask any questions:) thanks!

 

    

    

    

[Fossildude19]

Welcome to the Forum.  

 

Please post pictures, and not video. 

People don't want to have to download files to view them.  

[katherine1977]

ok i edited to only pics. got any ideas on this one?

[Fossildude19]

I am unfamiliar with opalized fossils, or "yabby buttons". 

Sorry, but I won't be helpful on the ID side here.   

[val horn]

What is a yabbi button. Is this like the worm burrows / Indian beads sometimes found in Florida.  Don’t know what you have. But it is a pretty opal

[Earendil]

From the looks of it, it's similar to a yabby button...

 

10 minutes ago, val horn said:

What is a yabbi button. Is this like the worm burrows / Indian beads sometimes found in Florida.  Don’t know what you have. But it is a pretty opal

A yabby button is a crayfish gastrolith, opalized, about 10-12 mm across. So this checks all the boxes. Some similar ones:

[val horn]

That is very neat.  Where can I find one

[Top Trilo]

24 minutes ago, val horn said:

That is very neat.  Where can I find one

If you mean find one yourself in the ground you have to go to Australia, some really cool fossils have been found opalized there

[val horn]

That really will be fun. Do the rules allow anyone to collect at these sites. I would love to see Australia when COVID is over

[Mike from North Queensland]

Looks to be a cut piece so possibly the end of a belemnite

[Earendil]

44 minutes ago, Mike from North Queensland said:

Looks to be a cut piece so possibly the end of a belemnite

It was cut by OP:

7 hours ago, katherine1977 said:

I have cut the bottom and a little of the side to be able to see inside better

 

[katherine1977]

i have cut some porch off the bottom only to be able to see the bottom end a little better, the top looks to be too uniformly rounded, so i don’t think anything has broken off from the top, but belemnite isn’t ruled out because i could of course be mistaken,  just that most belemnites i’ve seen are filled in, same with the yabby buttons, i’ve yet to find a pic of one that has the hole that this one does. this one looks like a mini volcano. here some good info on the inside of a belemnite: https://en.m.wikipedia.org/wiki/Belemnitida

[rodrex]

not a yabby button, probably not a fossil either. but now that it's been cut and polished, its lost any value it had as a specimen / potential fossil.

[Mahnmut]

Hello

All the yabbi buttons I have seen (on pictures mostly re a lot flatter than your specimen.

could be crinoid or small vertebra, but hard to say.

Although I would not go so far to say that any fossil looses any value the moment you make a cross section, I would also consider it wise to find out what it is before cutting it.

A lot of fantastic opal fossils have ended up as jewelry.

 

Best Regards,

J

 

[OzFossilphile]

 

On 3/4/2021 at 12:37 AM, katherine1977 said:

This came in a parcel of opal from Lightning Ridge. I have cut the bottom and a little of the side to be able to see inside better. The smaller opalized top portion is 8x10mm, the bottom opalized portion is 12x10mm.

I have been told this may be a yabby button, however I’m not sure because all the photos I’ve seen of yabby buttons don’t look a whole lot like this.

I appreciate any feedback, and feel free to ask any questions:) thanks!

 

    

    

    

To katherine1977  and to all above (apologies for such a late reply), I've been visiting and trading in Lightning Ridge opal for 30 years:

From the AOC (Lightning Ridge Opalised Fossil Museum aka Australian Opal Collection)

"Freshwater crayfish
The opalised gastroliths of freshwater crayfish [ONLY found in and around Lightning Ridge] are known locally as ‘yabby buttons.’ Crayfish use gastroliths to store calcium from their exoskeletons (‘shells’) before they moult, then release the calcium to harden their new protective coating. Fossil yabby buttons are usually around 10-12mm across."

This is very useful http://www.australianopalcentre.com/opalised-fossils.

Freshwater crayfish are called "yabby/yabbies" (from Aboriginal language). Modern yabbies also have the same type of gastrolith, virtually unchanged after around 100 million years.

 

Katherine, I doubt that your piece is (was) a yabby button. The definitive feature is the two rounded right-angle corners of your original piece. Yabby buttons are roughly circular with a convex top and a concentric concave bottom.

@yardrockpaleo --- it's probably not a belemnite, either; one end is likewise circular with a (usually host-rock-filled) conical concavity. Your photo shows the concave undersides of all those yabby buttons. Only a small % contain colour and field prices vary from AU$10 to as much as around AU$1,000 for those of excellent definition and gem colour.

My best guess is that it's a geological formation known as a 'kernel' which takes on various forms/shapes, but all have that distinctive concave underside; so, not a fossil.

As pointed out above, it's now badly damaged (although I'm sure your intentions were good) and impossible to identify.

[Budgie B]

On 10/5/2021 at 5:18 PM, OzFossilphile said:

 

To katherine1977  and to all above (apologies for such a late reply), I've been visiting and trading in Lightning Ridge opal for 30 years:

From the AOC (Lightning Ridge Opalised Fossil Museum aka Australian Opal Collection)

"Freshwater crayfish
The opalised gastroliths of freshwater crayfish [ONLY found in and around Lightning Ridge] are known locally as ‘yabby buttons.’ Crayfish use gastroliths to store calcium from their exoskeletons (‘shells’) before they moult, then release the calcium to harden their new protective coating. Fossil yabby buttons are usually around 10-12mm across."

This is very useful http://www.australianopalcentre.com/opalised-fossils.

Freshwater crayfish are called "yabby/yabbies" (from Aboriginal language). Modern yabbies also have the same type of gastrolith, virtually unchanged after around 100 million years.

 

Katherine, I doubt that your piece is (was) a yabby button. The definitive feature is the two rounded right-angle corners of your original piece. Yabby buttons are roughly circular with a convex top and a concentric concave bottom.

@yardrockpaleo --- it's probably not a belemnite, either; one end is likewise circular with a (usually host-rock-filled) conical concavity. Your photo shows the concave undersides of all those yabby buttons. Only a small % contain colour and field prices vary from AU$10 to as much as around AU$1,000 for those of excellent definition and gem colour.

My best guess is that it's a geological formation known as a 'kernel' which takes on various forms/shapes, but all have that distinctive concave underside; so, not a fossil.

As pointed out above, it's now badly damaged (although I'm sure your intentions were good) and impossible to identify.

This is some of my Yabby buttons Gastroliths that I find along rivers, and creeks, flood plain in western NSW. Some are modern some fossil. I found a opal one at lightning ridge but had to give it back as it was organised fossil dig. The opal one up the top in post is not a Yabby button.