Gizzard stone

[moatsy]

Found in a small Yellowcat wash, outside Moab, UT while scouring for petrified wood. Not near a uranium mine. Partially exposed and nothing else like it around the area all day. The wash was in Morrison material. About 3” x 5”. Super shiny even without washing. Thanks!

[Rockwood]

How do you propose to exclude the possibility that it was just tumbled smooth in the wash ?

[Fossildude19]

If I'm not mistaken, to positively identify gastroliths, they need to be found in a quantity, and usually with/within  other remains of the dinosaur that made use of them.

Could it be one?  Possibly.

Could it just be a tumbled stone?  Yes. 

 

I think the odds of it being a gastrolith are slim, myself. 

[moatsy]

Makes sense. It was a small wash at the top of a 200 foot high hill. This wash did not tumble it or anything else smooth, perhaps a different wash 20 mya. The reflectivity was why I wondered. It’s naturally shiny unlike the other dull agates around. Reflectivity has traditionally been the primary way of identifying these. Much more reflective while dry than even super smooth river stone. I may cut it or at least X-ray it to see if it’s an agate with an inclusion. 

[Rockwood]

1 hour ago, moatsy said:

perhaps a different wash 20 mya.

Washes x years x random durable stones that beat the odds and tumbled that far, is still probably greater odds than gastroliths unless you're like far out in the western interior seaway.

[moatsy]

I agree. Probably just a rock but yes WIS.

[Rockwood]

That has to be worth a few points !

@Troodon Care to weigh in on the probability ?

[Troodon]

  Tim said it best 

"If I'm not mistaken, to positively identify gastroliths, they need to be found in a quantity, and usually with/within  other remains of the dinosaur that made use of them.

Could it be one?  Possibly " 

 

Without evidence that supports it being a gastrolith there is no way to positively call it one.  

 

[Rockwood]

Hey, it beats no way. 

[snolly50]

@moatsy Here is an old post that discusses some of the features that gastroliths exhibit. The whole thread makes an interesting read, I believe. While you are facing an uphill battle establishing that an isolated stone is a gastrolith, the distinction reported between water-worn and gut polished may be of interest to you.